Boeing 737-200
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The Boeing 737 is an American
narrow-body A narrow-body aircraft or single-aisle aircraft is an airliner arranged along a single aisle, permitting up to 6-abreast airline seat, seating in a aircraft cabin, cabin less than in width. In contrast, a wide-body aircraft is a larger airliner ...
aircraft produced by
Boeing The Boeing Company, or simply Boeing (), is an American multinational corporation that designs, manufactures, and sells airplanes, rotorcraft, rockets, satellites, and missiles worldwide. The company also provides leasing and product support s ...
at its Renton factory in Washington. Developed to supplement the
Boeing 727 The Boeing 727 is an American Narrow-body aircraft, narrow-body airliner that was developed and produced by Boeing Commercial Airplanes. After the heavier Boeing 707, 707 quad-jet was introduced in 1958, Boeing addressed the demand for shorter ...
on short and thin routes, the
twinjet A twinjet or twin-engine jet is a jet aircraft powered by two jet engine, engines. A twinjet is able to fly well enough to land with a single working engine, making it safer than a single-engine aircraft in the event of failure of an engine. F ...
retained the 707 fuselage width and six abreast seating but with two underwing
Pratt & Whitney JT8D The Pratt & Whitney JT8D is a low-bypass (0.96 to 1) turbofan engine introduced by Pratt & Whitney in February 1963 with the inaugural flight of the Boeing 727. It was a modification of the Pratt & Whitney J52 turbojet engine which powered the ...
low-bypass turbofan engines. Envisioned in 1964, the initial 737-100 made its first flight in April 1967 and entered service in February 1968 with
Lufthansa Deutsche Lufthansa AG (), trading as the Lufthansa Group, is a German aviation group. Its major and founding subsidiary airline Lufthansa German Airlines, branded as Lufthansa, is the flag carrier of Germany. It ranks List of largest airlin ...
. The lengthened 737-200 entered service in April 1968, and evolved through four generations, offering several variants for 85 to 215 passengers. The First Generation 737-100/200 variants were powered by Pratt & Whitney JT8D low-bypass turbofan engines and offered seating for 85 to 130 passengers. Launched in 1980 and introduced in 1984, the Second Generation 737 Classic -300/400/500 variants were upgraded with more fuel-efficient CFM56-3 high-bypass turbofans and offered 110 to 168 seats. Introduced in 1997, the Third Generation
737 Next Generation The Boeing 737 Next Generation, commonly abbreviated as 737NG, or 737 Next Gen, is a twinjet, twin-engine narrow-body aircraft produced by Boeing Commercial Airplanes. Launched in 1993 as the third-generation derivative of the Boeing 737, it ha ...
(NG) -600/700/800/900 variants have updated CFM56-7 high-bypass turbofans, a larger wing and an upgraded
glass cockpit A glass cockpit is an aircraft cockpit that features an array of electronic (digital) flight instrument display device, displays, typically large liquid-crystal display, LCD screens, rather than traditional Analog device, analog dials and gauges ...
, and seat 108 to 215 passengers. The latest, and Fourth Generation, the
737 MAX The Boeing 737 MAX is a series of narrow-body aircraft developed by Boeing Commercial Airplanes as the fourth generation of the Boeing 737. It succeeds the Boeing 737 Next Generation and incorporates more efficient CFM International LEAP engi ...
-7/8/9/10 variants, powered by improved CFM LEAP-1B high-bypass turbofans and accommodating 138 to 204 people, entered service in 2017.
Boeing Business Jet A Boeing Business Jet (BBJ) is a version of a Boeing Commercial Airplanes, Boeing jet airliner with modifications to serve the private, head of state, and corporate jet market. The first BBJ, based on the 737-700, rolled out on July 26, 1998; a ...
versions have been produced since the 737NG, as well as military models. , 16,956 Boeing 737s have been ordered and 12,092 delivered. It was the highest-selling commercial aircraft until being surpassed by the competing
Airbus A320 family The Airbus A320 family is a series of narrow-body airliners developed and produced by Airbus. The A320 was launched in March 1984, first flew on 22 February 1987, and was introduced in April 1988 by Air France. The first member of the fami ...
in October 2019, but maintains the record in total deliveries. Initially, its main competitor was the
McDonnell Douglas DC-9 The McDonnell Douglas DC-9 is an American five-abreast, single-aisle aircraft designed by the Douglas Aircraft Company. It was initially produced as the Douglas DC-9 prior to August 1967, after which point the company had merged with McDonnell ...
, followed by its
MD-80 The McDonnell Douglas MD-80 is a series of five-abreast narrow-body aircraft, single-aisle airliners developed by McDonnell Douglas. It was produced by the developer company until August 1997 and then by Boeing Commercial Airplanes. The MD-80 ...
/
MD-90 The McDonnell Douglas (later Boeing) MD-90 is a retired American five-abreast narrow-body aircraft, single-aisle airliner developed by McDonnell Douglas from its successful model McDonnell Douglas MD-80, MD-80. The airliner was produced by the ...
derivatives. In 2013, the global 737 fleet had completed more than 184 million flights over 264 million block hours since its entry into service. The 737 MAX, designed to compete with the
A320neo The Airbus A320neo family is an incremental development of the A320 family of narrow-body airliners produced by Airbus. The A320neo family (''neo'' being Greek for "new", as well as an acronym for "new engine option") is based on the enhance ...
, was grounded worldwide between March 2019 and November 2020 following two fatal crashes.


Development


Initial design

Boeing had been studying short-haul jet aircraft designs, and saw a need for a new aircraft to supplement the 727 on short and thin routes.Transport News: Boeing Plans Jet.
" ''
The New York Times ''The New York Times'' (''NYT'') is an American daily newspaper based in New York City. ''The New York Times'' covers domestic, national, and international news, and publishes opinion pieces, investigative reports, and reviews. As one of ...
'', July 17, 1964. Retrieved: February 26, 2008.
Preliminary design work began on May 11, 1964, based on research that indicated a market for a fifty to sixty passenger airliner flying routes of . The initial concept featured
podded engine A podded engine is a jet engine that has been built up and integrated in its nacelle. This may be done in a podding facility as part of an aircraft assembly process. The nacelle contains the engine, engine mounts and parts which are required to ...
s on the aft fuselage, a
T-tail A T-tail is an empennage wikt:configuration, configuration in which the tailplane of an aircraft is mounted to the top of the vertical stabilizer, fin. The arrangement looks like the capital letter T, hence the name. The T-tail differs fr ...
as with the 727, and five-abreast seating. Engineer Joe Sutter relocated the engines to the wings which lightened the structure and simplified the accommodation of six-abreast seating in the fuselage. The engine
nacelle A nacelle ( ) is a streamlined container for aircraft parts such as Aircraft engine, engines, fuel or equipment. When attached entirely outside the airframe, it is sometimes called a pod, in which case it is attached with a Hardpoint#Pylon, pylo ...
s were mounted directly to the underside of the wings, without pylons, allowing the
landing gear Landing gear is the undercarriage of an aircraft or spacecraft that is used for taxiing, takeoff or landing. For aircraft, it is generally needed for all three of these. It was also formerly called ''alighting gear'' by some manufacturers, s ...
to be shortened, thus lowering the fuselage to improve baggage and passenger access. Relocating the engines from the aft fuselage also allowed the
horizontal stabilizer A tailplane, also known as a horizontal stabilizer, is a small lifting surface located on the tail ( empennage) behind the main lifting surfaces of a fixed-wing aircraft as well as other non-fixed-wing aircraft such as helicopters and gyroplan ...
to be attached to the aft fuselage instead of as a T-tail. Many designs for the engine attachment strut were tested in the wind tunnel and the optimal shape for high speed was found to be one which was relatively thick, filling the narrow channels formed between the wing and the top of the nacelle, particularly on the outboard side. At the time, Boeing was far behind its competitors; the SE 210 Caravelle had been in service since 1955, and the
BAC One-Eleven The BAC One-Eleven (BAC-111, BAC 1-11) is a retired early jet airliner produced by the British Aircraft Corporation (BAC). Conceived by Hunting Aircraft as a 30-seat jet, before its merger into BAC in 1960, it was launched as an 80-seat airl ...
(BAC-111), Douglas DC-9, and
Fokker F28 The Fokker F28 Fellowship is a twin-engined, short-range jet airliner designed and built by Dutch aircraft manufacturer Fokker. Following the Fokker F27 Friendship, an early and commercially successful turboprop-powered regional airliner, Fokk ...
were already into flight certification. To expedite development, Boeing used 60% of the structure and systems of the existing 727, particularly the fuselage, which differs in length only. This 148-inch (3.76 m) wide fuselage cross-section permitted six-abreast seating compared to the rivals' five-abreast. The 727's fuselage was derived from the 707. The proposed wing
airfoil An airfoil (American English) or aerofoil (British English) is a streamlined body that is capable of generating significantly more Lift (force), lift than Drag (physics), drag. Wings, sails and propeller blades are examples of airfoils. Foil (fl ...
sections were based on those of the 707 and 727, but somewhat thicker; altering these sections near the nacelles achieved a substantial drag reduction at high Mach numbers. The engine chosen was the
Pratt & Whitney JT8D The Pratt & Whitney JT8D is a low-bypass (0.96 to 1) turbofan engine introduced by Pratt & Whitney in February 1963 with the inaugural flight of the Boeing 727. It was a modification of the Pratt & Whitney J52 turbojet engine which powered the ...
-1 low-bypass ratio turbofan engine, delivering of thrust. The concept design was presented in October 1964 at the Air Transport Association maintenance and engineering conference by chief project engineer Jack Steiner, where its elaborate
high-lift device In aircraft design and aerospace engineering, a high-lift device is a component or mechanism on an aircraft's wing that increases the amount of lift produced by the wing. The device may be a fixed component, or a movable mechanism which is deplo ...
s raised concerns about
maintenance The technical meaning of maintenance involves functional checks, servicing, repairing or replacing of necessary devices, equipment, machinery, building infrastructure and supporting utilities in industrial, business, and residential installa ...
costs and dispatch reliability.


Major design developments

The original 737 continued to be developed into thirteen passenger, cargo, corporate and military variants. These were later divided into what has become known as the four generations of the Boeing 737 family: * The first generation "Original" series: the 737-100 and -200, also the military T-43 and CT-43, launched February 1965. * The second generation "Classic" series: 737-300, -400 and -500, launched in 1979. * The third generation "Next Generation" series: 737-600, -700, -800 and -900, also the military C-40 and P-8, launched late 1993. * The fourth generation 737 MAX series: 737-7, -8, -9 and -10, launched August 2011.


Launch

The launch decision for the $150 million (~$ in ) development was made by the board on February 1, 1965. The sales pitch was big-jet comfort on short-haul routes.
Lufthansa Deutsche Lufthansa AG (), trading as the Lufthansa Group, is a German aviation group. Its major and founding subsidiary airline Lufthansa German Airlines, branded as Lufthansa, is the flag carrier of Germany. It ranks List of largest airlin ...
became the launch customer on February 19, 1965, with an order for 21 aircraft, worth $67 million (~$ in )"German Airline Buys 21 Boeing Short-Range Jets." ''
The Washington Post ''The Washington Post'', locally known as ''The'' ''Post'' and, informally, ''WaPo'' or ''WP'', is an American daily newspaper published in Washington, D.C., the national capital. It is the most widely circulated newspaper in the Washington m ...
'', February 20, 1965. Retrieved: February 26, 2008.
after the airline had been assured by Boeing that the 737 project would not be canceled.Wallace, J
"Boeing delivers its 5,000th 737."
''Seattle Post-Intelligencer'', February 13, 2006. Retrieved June 7, 2011.
Consultation with Lufthansa over the previous winter had resulted in the seating capacity being increased to 100. On April 5, 1965, Boeing announced an order by
United Airlines United Airlines, Inc. is a Major airlines of the United States, major airline in the United States headquartered in Chicago, Chicago, Illinois that operates an extensive domestic and international route network across the United States and six ...
for 40 737s. United wanted a slightly larger capacity than the 737-100, so the fuselage was stretched ahead of, and behind the wing. The longer version was designated the 737-200, with the original short-body aircraft becoming the 737-100. Detailed design work continued on both variants simultaneously.


Introduction

The first -100 was rolled out on January 17, 1967, and took its maiden flight on April 9, 1967, piloted by Brien Wygle and Lew Wallick. After several test flights the
Federal Aviation Administration The Federal Aviation Administration (FAA) is a Federal government of the United States, U.S. federal government agency within the United States Department of Transportation, U.S. Department of Transportation that regulates civil aviation in t ...
(FAA) issued Type Certificate A16WE certifying the 737-100 for commercial flight on December 15, 1967."Type Certificate Data Sheet A16WE."
''faa.gov.'' Retrieved: September 3, 2010.
It was the first aircraft to have, as part of its initial certification, approval for Category II approaches, which refers to a precision instrument approach and landing with a decision height between . Lufthansa received its first aircraft on December 28, 1967, and on February 10, 1968, became the first non-American airline to launch a new Boeing aircraft. Lufthansa was the only significant customer to purchase the 737-100 and only 30 aircraft were produced. The -200 was rolled out on June 29, 1967, and had its maiden flight on August 8, 1967. It was then certified by the FAA on December 21, 1967. The inaugural flight for United Airlines took place on April 28, 1968, from
Chicago Chicago is the List of municipalities in Illinois, most populous city in the U.S. state of Illinois and in the Midwestern United States. With a population of 2,746,388, as of the 2020 United States census, 2020 census, it is the List of Unite ...
to
Grand Rapids, Michigan Grand Rapids is the largest city and county seat of Kent County, Michigan, United States. With a population of 198,917 at the 2020 United States census, 2020 census and estimated at 200,117 in 2024, Grand Rapids is the List of municipalities ...
. The lengthened -200 was widely preferred over the -100 by airlines. The improved version, the 737-200 Advanced, was introduced into service by
All Nippon Airways (ANA) is a Japanese airline headquartered in Minato, Tokyo. ANA operates services to both domestic and international destinations and is Japan's largest airline, ahead of its main rival flag carrier Japan Airlines. the airline has approximate ...
on May 20, 1971. The 737 original model with its variants, known later as the ''Boeing 737 Original'', initially competed with SE 210 Caravelle and BAC-111 due to their earlier entry into service and later primarily with the
McDonnell Douglas McDonnell Douglas Corporation was a major American Aerospace manufacturer, aerospace manufacturing corporation and defense contractor, formed by the merger of McDonnell Aircraft and the Douglas Aircraft Company in 1967. Between then and its own ...
DC-9, then its
MD-80 The McDonnell Douglas MD-80 is a series of five-abreast narrow-body aircraft, single-aisle airliners developed by McDonnell Douglas. It was produced by the developer company until August 1997 and then by Boeing Commercial Airplanes. The MD-80 ...
derivatives as the three European short-haul single aisles slowly withdrew from the competition. Sales were low in the early 1970s and, after a peak of 114 deliveries in 1969, only 22 737s were shipped in 1972 with 19 in backlog. The
US Air Force The United States Air Force (USAF) is the Air force, air service branch of the United States Department of Defense. It is one of the six United States Armed Forces and one of the eight uniformed services of the United States. Tracing its ori ...
saved the program by ordering T-43s, which were modified Boeing 737-200s. African airline orders kept the production running until the 1978 US
Airline Deregulation Act The Airline Deregulation Act is a 1978 United States federal law that deregulated the airline industry in the United States, removing federal control over such areas as fares, routes, and market entry of new airlines. The act gradually phase ...
, which improved demand for six-abreast narrow-body aircraft. Demand further increased after being re-engined with the CFM56. The 737 went on to become the highest-selling commercial aircraft in terms of orders until surpassed by the competing
Airbus A320 family The Airbus A320 family is a series of narrow-body airliners developed and produced by Airbus. The A320 was launched in March 1984, first flew on 22 February 1987, and was introduced in April 1988 by Air France. The first member of the fami ...
in October 2019, but maintains the record in total deliveries. The fuselage is manufactured in
Wichita, Kansas Wichita ( ) is the List of cities in Kansas, most populous city in the U.S. state of Kansas and the county seat of Sedgwick County, Kansas, Sedgwick County. As of the 2020 United States census, 2020 census, the population of the city was 397, ...
, by Boeing spin-off company
Spirit AeroSystems Spirit AeroSystems Holdings, Inc. is an American Manufacturing, manufacturer of aerostructures for commercial airplanes, headquartered in Wichita, Kansas. The company produces fuselage sections for Boeing's Boeing 737, 737 and Boeing 787 Dreaml ...
, before being moved by rail to Renton. The Renton factory has three assembly lines for the 737 MAX; a fourth is planned to open at the Everett factory in 2024.


Generations and variants


737 Original (first generation)

The ''Boeing 737 Original'' is the name given to the -100 and -200 series of the Boeing 737 family. These are sometimes referred to by the nickname ''737 Jurassic''.


737-100

The initial model was the 737-100, the smallest variant of the 737 aircraft family, which was launched in February 1965 and entered service with
Lufthansa Deutsche Lufthansa AG (), trading as the Lufthansa Group, is a German aviation group. Its major and founding subsidiary airline Lufthansa German Airlines, branded as Lufthansa, is the flag carrier of Germany. It ranks List of largest airlin ...
in February 1968. In 1968, its unit cost was . A total of just 30 737-100s were produced: 22 for Lufthansa, 5 for
Malaysia–Singapore Airlines Malaysia–Singapore Airlines (abbreviation: MSA) was the binational flag carrier of Malaysia and Singapore that operated from 1966 to 1972. The airline originated as Malayan Airways (MAL), established in 1937 to provide air services within Bri ...
(MSA) and 2 for
Avianca Avianca S.A. (acronym in Spanish for ''Aerovias de Colombia S.A.'', "Airways of Colombia", and stylized as avianca since October 2023) is the largest airline in Colombia. It has been the flag carrier of Colombia since December 5, 1919, when it ...
with the final aircraft delivered to MSA on October 31, 1969. This variant was largely overshadowed by its bigger 737-200 sibling, which entered service two months later. The original engine nacelles incorporated thrust reversers taken from the 727 outboard nacelles. They proved to be relatively ineffective and tended to lift the aircraft up off the runway when deployed. This reduced the downforce on the main wheels thereby reducing the effectiveness of the wheel brakes. In 1968, an improvement to the
thrust reversal Thrust reversal, also called reverse thrust, is the temporary diversion of an aircraft engine's thrust for it to act against the forward travel of the aircraft, providing deceleration. Thrust reverser systems are featured on many jet aircraft to ...
system was introduced. A 48-inch tailpipe extension was added and new target-style thrust reversers were incorporated. The thrust reverser doors were set 35 degrees away from the vertical to allow the exhaust to be deflected inboard and over the wings and outboard and under the wings. The improvement became standard on all aircraft after March 1969, and a retrofit was provided for active aircraft. Longer nacelle/wing fairings were introduced, and the airflow over the flaps and slats was improved. The production line also introduced an improvement to the flap system, allowing increased use during takeoff and landing. All these changes gave the aircraft a boost to payload and range, and improved short-field performance. Both the first and last 737-100s became the last 737-100s in service. The first aircraft used by Boeing as prototype under registration N73700 was later ordered by and delivered to
NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...
on July 26, 1973, which then operated it under registration N515NA and retired after 30 years on September 27, 2003. The last 737-100 built and also the last operating was originally sold to MSA, transferred to Air Florida, before being used as a VIP aircraft by the Mexican Air Force for 23 years under registration TP-03. TP-03 would be broken up in 2006. The first 737-100, NASA 515, is on static display in the
Museum of Flight The Museum of Flight is a private Nonprofit organization, non-profit Aircraft, air and Spacecraft, space museum in the Seattle metropolitan area. It is located at the southern end of Boeing Field, King County International Airport (Boeing Fi ...
in
Seattle Seattle ( ) is the most populous city in the U.S. state of Washington and in the Pacific Northwest region of North America. With a population of 780,995 in 2024, it is the 18th-most populous city in the United States. The city is the cou ...
and is the last surviving example of the type.


737-200

The 737-200 was a 737-100 with an extended fuselage, launched by an order from United Airlines in 1965 and entered service with the launch customer in April 1968. Its unit cost was US$4.0M (1968) ($M today). The -200's unit cost was US$5.2M (1972) ($M today). The 737-200 Advanced is an improved version of the -200, introduced into service by
All Nippon Airways (ANA) is a Japanese airline headquartered in Minato, Tokyo. ANA operates services to both domestic and international destinations and is Japan's largest airline, ahead of its main rival flag carrier Japan Airlines. the airline has approximate ...
on May 20, 1971. After aircraft #135, the 737-200 Advanced has improved aerodynamics, automatic wheel brakes, more powerful engines, more fuel capacity, and hence a 15% increase in payload and range over the original -200s and respectively -100s. The 737-200 Advanced became the production standard in June 1971. Boeing also provided the 737-200C ( Combi), which allowed for conversion between passenger and cargo use and the 737-200QC (Quick Change), which facilitated a rapid conversion between roles. The 1,114th and last delivery of a -200 series aircraft was in August 1988 to Xiamen Airlines."About the 737 Family."
''The Boeing Company''. Retrieved: December 20, 2007.
Nineteen 737-200s, designated T-43, were used to train aircraft navigators for the U.S. Air Force. Some were modified into CT-43s, which are used to transport passengers, and one was modified as the NT-43A Radar Test Bed. The first was delivered on July 31, 1973, and the last on July 19, 1974. The
Indonesian Air Force The Indonesian Air Force (, sometimes shortened as IDAF / IdAF) is the Air force, aerial branch of the Indonesian National Armed Forces. The Indonesian Air Force is headquartered in Jakarta, Indonesia, and is headed by the Chief of Staff of th ...
ordered three modified 737-200s, designated ''Boeing 737-2X9 Surveiller''. They were used as Maritime reconnaissance (MPA)/transport aircraft, fitted with SLAMMAR (Side-looking Multi-mission Airborne Radar). The aircraft were delivered between May 1982 and October 1983.After 40 years, in March 2008, the final 737-200 aircraft in the U.S. flying scheduled passenger service were phased out, with the last flights of
Aloha Airlines Aloha Airlines was an airline in the United States that operated passenger flights from 1946 until 2008. It was headquartered in Honolulu, Hawaii, operating from its hub at Honolulu International Airport (now Daniel K. Inouye International Air ...
. As of 2018, the variant still saw regular service through North American charter operators such as Sierra Pacific Airlines. The short-field capabilities of the 737-200 led Boeing to offer the "Unpaved Strip Kit" (see the Air North example, right). This option reduced foreign object damage when operated on remote, unimproved or unpaved runways, that competing jetliners could not use safely. The kit included a gravel deflector on the nose gear and a vortex dissipator extending from the front of the engine.
Alaska Airlines Alaska Airlines is a major American airline headquartered in SeaTac, Washington, within the Seattle metropolitan area. It is the fifth-largest airline in North America when measured by scheduled passengers carried, as of 2024. Alaska, togethe ...
used the gravel kit for some of its
combi aircraft Combi aircraft in commercial aviation are aircraft that can be used to carry either passengers as an airliner, or cargo as a freighter, and may have a partition in the aircraft cabin to allow both uses at the same time in a mixed passenger/fre ...
rural operations in
Alaska Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the north ...
until retiring its -200 fleet in 2007. Air Inuit, Nolinor Aviation and Buffalo Airways still use the gravel kit in Northern Canada.
Canadian North Bradley Air Services, operating as Canadian North, is a wholly Inuit-owned airline headquartered in Kanata, Ontario, Canada. It operates scheduled passenger services to communities in the Northwest Territories, Nunavut, and the Nunavik region ...
also operated a gravel-kitted 737-200 Combi, but this was due to be retired in early 2023. , a relatively high number of 737-200s remain in service compared to other early jet airliners, with fifty examples actively flying for thirty carriers. During the 737 MAX groundings, older 737s, including the 200 and Classic series, were in demand for leasing. C-GNLK, one of Nolinor's 737-200s, is the oldest jet airliner in commercial service as of 2024, having entered service 50 years prior in 1974.


737 Classic (second generation)

The ''Boeing 737 Classic'' is the name given to the 737-300/400/500 series after the introduction of the -600/700/800/900 series of the Boeing 737 family. Produced from 1984 to 2000, a total of 1,988 Classic series were delivered. Close to the next major upgrade of single aisle aircraft at Airbus and Boeing, the price of jet fuel reached a peak in 2008, when airlines devoted 40% of the retail price of an air ticket to pay for fuel, versus 15% in 2000. Consequently, in that year carriers retired Boeing 737 Classic aircraft to reduce fuel consumption; replacements consisted of more efficient 737 Next Generation or A320 family aircraft. On June 4, 2008,
United Airlines United Airlines, Inc. is a Major airlines of the United States, major airline in the United States headquartered in Chicago, Chicago, Illinois that operates an extensive domestic and international route network across the United States and six ...
announced it would retire all 94 of its Classic 737 aircraft (64 737-300 and 30 737-500 aircraft), replacing them with A320 family jets taken from its Ted subsidiary, which has been shut down. This intensified the competition between the two giant aircraft manufacturers, which has since become a duopoly competition. An optional upgrade with
winglet Wingtip devices are intended to improve the efficiency of fixed-wing aircraft by reducing drag. Although there are several types of wing tip devices which function in different manners, their intended effect is always to reduce an aircraft' ...
s became available for the Classic and NG series. * The 737-300 and 737-500 can be retrofitted with Aviation Partners Boeing winglets, and the 737-300 retrofitted with winglets is designated the -300SP (Special Performance). * WestJet was to launch the 737-600 with winglets, but dropped them in 2006.


737-300

Development began in 1979 for the 737's first major revision, which was originally introduced as the 'new generation' of the 737. Boeing wanted to increase capacity and range, incorporating improvements to upgrade the aircraft to modern specifications, while also retaining commonality with previous 737 variants. In 1980, preliminary aircraft specifications of the variant, dubbed 737-300, were released at the
Farnborough Airshow The Farnborough International Airshow is a trade exhibition for the aerospace and defence industries, where civilian and military aircraft are demonstrated to potential customers and investors in Farnborough, Hampshire. Since its first show in ...
. This first major upgrade series was later renamed 737 Classic. It competed primarily with the MD-80, its later derivative the
MD-90 The McDonnell Douglas (later Boeing) MD-90 is a retired American five-abreast narrow-body aircraft, single-aisle airliner developed by McDonnell Douglas from its successful model McDonnell Douglas MD-80, MD-80. The airliner was produced by the ...
, and the newcomer
Airbus A320 family The Airbus A320 family is a series of narrow-body airliners developed and produced by Airbus. The A320 was launched in March 1984, first flew on 22 February 1987, and was introduced in April 1988 by Air France. The first member of the fami ...
. Boeing engineer Mark Gregoire led a design team, which cooperated with
CFM International CFM International is a Franco-American aircraft engine manufacturer. The company is a joint venture between GE Aerospace and Safran Aircraft Engines (formerly known as Snecma) and is headquartered in Cincinnati, Ohio. It was founded in 1974 to bu ...
to select, modify and deploy a new engine and nacelle that would make the 737-300 into a viable aircraft. They chose the CFM56-3B-1 high-bypass
turbofan A turbofan or fanjet is a type of airbreathing jet engine that is widely used in aircraft engine, aircraft propulsion. The word "turbofan" is a combination of references to the preceding generation engine technology of the turbojet and the add ...
engine to power the aircraft, which yielded significant gains in fuel economy and a reduction in noise, but also posed an engineering challenge, given the low ground clearance of the 737 and the larger diameter of the engine over the original Pratt & Whitney engines. Gregoire's team and CFM solved the problem by reducing the size of the fan (which made the engine slightly less efficient than it had been forecast to be), placing the engine ahead of the wing, and by moving engine accessories to the sides of the engine pod, giving the engine a distinctive non-circular "hamster pouch" air intake. Earlier customers for the CFM56 included the U.S. Air Force with its program to re-engine KC-135 tankers. The passenger capacity of the aircraft was increased to 149 by extending the fuselage around the wing by . The wing incorporated several changes for improved aerodynamics. The wingtip was extended , and the wingspan by . The leading-edge slats and trailing-edge flaps were adjusted. The tailfin was redesigned, the flight deck was improved with the optional EFIS (Electronic Flight Instrumentation System), and the passenger cabin incorporated improvements similar to those developed on the
Boeing 757 The Boeing 757 is an American Narrow-body aircraft, narrow-body airliner designed and built by Boeing Commercial Airplanes. The then-named 7N7, a twinjet successor for the trijet Boeing 727, 727, received its first orders in August 1978. The ...
. The prototype -300, the 1,001st 737 built, first flew on February 24, 1984, with pilot Jim McRoberts. It and two production aircraft flew a nine-month-long certification program. The 737-300 retrofitted with Aviation Partners' winglets was designated the -300SP (''Special Performance''). The 737-300 was replaced by the 737-700 of the Next Generation series.


737-400

The 737-400 was launched in 1985 to fill the gap between the 737-300 and the 757-200. In June 1986, Boeing announced the development of the 737-400, which stretched the fuselage a further , increasing the capacity to 188 passengers, and requiring a tail bumper to prevent
tailstrike In aviation, a tailstrike or tail strike occurs when the tail or empennage of an aircraft strikes the ground or other stationary object. This can happen with a fixed-wing aircraft with tricycle undercarriage, in both takeoff where the pilot r ...
s during take-off and a strengthened
wing spar In a fixed-wing aircraft, the spar is often the main structural member of the wing, running spanwise at right angles (or thereabouts depending on wing sweep) to the fuselage. The spar carries flight loads and the weight of the wings while on ...
. The -400s first flight was on February 19, 1988, and, after a seven-month/500-hour flight-testing run, entered service with
Piedmont Airlines Piedmont Airlines, Inc. ( ) is an American regional airline headquartered at the Salisbury Regional Airport in Wicomico County, Maryland, near the Salisbury, Maryland, city of Salisbury. The airline is a wholly-owned subsidiary of the American ...
that October. The last two -400s, i.e. the last 737 Classics series, were delivered to CSA Czech Airlines on February 28, 2000. The 737-400 was replaced by the 737-800 of the Next Generation series. The 737-400SF was a 737-400 converted to freighter, though it was not a model delivered by Boeing and hence the nickname ''Special Freighter (SF)''.
Alaska Airlines Alaska Airlines is a major American airline headquartered in SeaTac, Washington, within the Seattle metropolitan area. It is the fifth-largest airline in North America when measured by scheduled passengers carried, as of 2024. Alaska, togethe ...
was the first to convert one of their 400s from regular service to an aircraft with the ability to handle 10 pallets. The airline had also converted five more into fixed combi aircraft for half passenger and freight. These 737-400 Combi aircraft were retired in 2017 and replaced by the 737-700F of the Next Generation series.


737-500

The 737-500 was offered as a modern and direct replacement of the 737-200. It was launched in 1987 by
Southwest Airlines Southwest Airlines Co., or simply Southwest, is a Major airlines of the United States, major airline in the United States that formerly operated on a low-cost carrier model. It is headquartered in the Love Field, Dallas, Love Field neighborhood ...
, with an order for 20 aircraft, and it flew for the first time on June 30, 1989. A single prototype flew 375 hours for the certification process, and on February 28, 1990,
Southwest Airlines Southwest Airlines Co., or simply Southwest, is a Major airlines of the United States, major airline in the United States that formerly operated on a low-cost carrier model. It is headquartered in the Love Field, Dallas, Love Field neighborhood ...
received the first delivery. The -500 incorporated the improvements of the 737 Classic series, allowing longer routes with fewer passengers to be more economical than with the 737-300. The fuselage length of the 737-500 is longer than the 737-200, accommodating up to 140 passengers. Both glass and older-style mechanical cockpits arrangements were available. Using the CFM56-3 engine also gave a 25 percent increase in
fuel efficiency Fuel efficiency (or fuel economy) is a form of thermal efficiency, meaning the ratio of effort to result of a process that converts chemical energy, chemical potential energy contained in a carrier (fuel) into kinetic energy or Mechanical work, w ...
over the older 737-200s P&W engines. The 737-500 has faced accelerated retirement due to its smaller size, after 21 years in service compared to 24 years for the -300. While a few 737-300s were slated for freighter conversion, no demand at all existed for a -500 freighter conversion. The 737-500 was replaced by the 737-600 of the Next Generation series, though the -600 was not as successful in total orders as the -500.


737 NG (third generation)

The ''Boeing 737 Next Generation'', abbreviated as ''737 Next Gen'' or ''737NG'', is the name given to the -600, -700, -800 and -900 variants. It has been produced since 1996 and introduced in 1997, with a total order of 7,097 aircraft, of which 7,031 have been delivered . The primary goal was to re-engine the 737 with the high bypass ratio CFM56-7. By the early 1990s, as the MD-80 slowly withdrew from the competition following the introduction of the MD-90, it had become clear that the new A320 family was a serious threat to Boeing's market share. Airbus won previously loyal 737 customers, such as Lufthansa and United Airlines. In November 1993, to stay in the single aisle competition, Boeing's board of directors authorized the Next Generation program to mainly upgrade the 737 Classic series. In late 1993, after engineering trade studies and discussions with major customers, Boeing proceeded to launch a second derivative of the Boeing 737, the
737 Next Generation The Boeing 737 Next Generation, commonly abbreviated as 737NG, or 737 Next Gen, is a twinjet, twin-engine narrow-body aircraft produced by Boeing Commercial Airplanes. Launched in 1993 as the third-generation derivative of the Boeing 737, it ha ...
(NG) -600/700/800/900 series. It featured a redesigned wing with a wider wingspan and larger area, greater fuel capacity, longer range and higher MTOWs. It was equipped with CFM56-7 high pressure ratio engines, a
glass cockpit A glass cockpit is an aircraft cockpit that features an array of electronic (digital) flight instrument display device, displays, typically large liquid-crystal display, LCD screens, rather than traditional Analog device, analog dials and gauges ...
, and upgraded interior configurations. The four main models of the series can accommodate seating for 108 to 215 passengers. It was further developed into additional versions such as the corporate
Boeing Business Jet A Boeing Business Jet (BBJ) is a version of a Boeing Commercial Airplanes, Boeing jet airliner with modifications to serve the private, head of state, and corporate jet market. The first BBJ, based on the 737-700, rolled out on July 26, 1998; a ...
(BBJ) and military
P-8 Poseidon The Boeing P-8 Poseidon is an American maritime patrol aircraft, maritime patrol and reconnaissance aircraft developed and produced by Boeing Defense, Space & Security. It was developed for the United States Navy as a derivative of the civilian ...
aircraft. Following the merger between Boeing with McDonnell Douglas in 1997, the primary competitor for the 737NG series remained only the A320 family.


737-600

The 737-600 was the smallest of the Next-Generation models, replacing the 737-500. It had no winglets and was similar in size to the
Airbus A318 The Airbus A318, nicknamed the "Baby Bus", is the smallest and least numerous variant airliner of the Airbus A320 family. The A318 carries 107 to 132 passengers and has a maximum range of . Final assembly of the aircraft took place in Hambur ...
. Launch customer
Scandinavian Airlines The Scandinavian Airlines System (SAS), commonly known as Scandinavian Airlines, is the national airline of Denmark, Norway, and Sweden. It is part of SAS Group and is headquartered in Solna, Sweden. Including its subsidiaries SAS Link and ...
(SAS) placed its order in March 1995 and took the first delivery in September 1998. A total of 69 aircraft were produced, with the last one delivered to WestJet in 2006.


737-700

The 737-700, the first variant of the Next-Generation, was launched in November 1993 with an order of 63 aircraft. The -700 seats 126 passengers in a two-class or 149 passengers in a one-class layout. Launch customer
Southwest Airlines Southwest Airlines Co., or simply Southwest, is a Major airlines of the United States, major airline in the United States that formerly operated on a low-cost carrier model. It is headquartered in the Love Field, Dallas, Love Field neighborhood ...
took the first delivery in December 1997. The 737-700 replaced the 737-300 and competes with the
Airbus A319 The Airbus A319 is a member of the Airbus A320 family of short- to medium-range, narrow-body, commercial passenger twin-engine jet airliners manufactured by Airbus. The A319 carries 124 to 156 passengers and has a maximum range of . Final ass ...
. The ''737-700C'' is a convertible version where the seats can be removed to carry cargo instead. There is a large door on the left side of the aircraft. The
United States Navy The United States Navy (USN) is the naval warfare, maritime military branch, service branch of the United States Department of Defense. It is the world's most powerful navy with the largest Displacement (ship), displacement, at 4.5 millio ...
was the launch customer for the 737-700C under the military designation
C-40 Clipper The Boeing C-40 Clipper is a military version of the Boeing 737 Next Generation used to transport cargo and passengers. It is used by the United States Navy, United States Air Force, Air Force, and United States Marine Corps, Marine Corps. Th ...
. The ''737-700ER'' (Extended
Range Range may refer to: Geography * Range (geographic), a chain of hills or mountains; a somewhat linear, complex mountainous or hilly area (cordillera, sierra) ** Mountain range, a group of mountains bordered by lowlands * Range, a term used to i ...
) was launched on January 31, 2006, and featured the fuselage of the 737-700 and the wings and landing gear of the 737-800. A 737-700ER can typically accommodate 126 passengers in two classes with a range similar to the Airbus A319LR.


737-800

The 737-800 was a stretched version of the 737-700 launched on September 5, 1994, and first flew on July 31, 1997. The -800 seats 162 passengers in a two-class or 189 passengers in a high-density, one-class layout. Launch customer
Hapag-Lloyd Flug Hapag-Lloyd Flug GmbH (known as Hapagfly GmbH between 2005 and 2007) was a German leisure airline headquartered in Langenhagen, Lower Saxony, that was originally founded by Hapag-Lloyd and later became a subsidiary of TUI Group. It operated sc ...
(now TUIfly) received the first one in April 1998. The 737-800 replaced directly the -400 and aging 727-200 of US airlines. It filled also the gap left by Boeing's decision to discontinue the MD-80 and
MD-90 The McDonnell Douglas (later Boeing) MD-90 is a retired American five-abreast narrow-body aircraft, single-aisle airliner developed by McDonnell Douglas from its successful model McDonnell Douglas MD-80, MD-80. The airliner was produced by the ...
aircraft, following Boeing's merger with
McDonnell Douglas McDonnell Douglas Corporation was a major American Aerospace manufacturer, aerospace manufacturing corporation and defense contractor, formed by the merger of McDonnell Aircraft and the Douglas Aircraft Company in 1967. Between then and its own ...
. The 737-800 is the most widely used narrowbody aircraft and competes primarily with the Airbus A320.


737-900

The 737-900 was launched in November 1997 and took its first flight on August 3, 2000. It is longer than the -800, but retains the
MTOW The maximum takeoff weight (MTOW) or maximum gross takeoff weight (MGTOW) or maximum takeoff mass (MTOM) of an aircraft, also known as the maximum structural takeoff weight or maximum structural takeoff mass, is the maximum weight at which the p ...
, fuel capacity, and exit configuration of the -800, essentially trading range for capacity. The exit configuration limits its seat capacity to approximately 177 in a two class and 189 in a high-density, one class layout. Launch customer
Alaska Airlines Alaska Airlines is a major American airline headquartered in SeaTac, Washington, within the Seattle metropolitan area. It is the fifth-largest airline in North America when measured by scheduled passengers carried, as of 2024. Alaska, togethe ...
received the first delivery in May 2001. The ''737-900ER'' (Extended Range), the newest and largest variant of the 737NG generation, was launched in July 2005, first flew in September 2006, and first delivered to launch customer Lion Air in April 2007. An additional pair of exit doors and a flat
rear pressure bulkhead The aft pressure bulkhead or rear pressure bulkhead is the rear component of the pressure seal in all aircraft that cruise in a tropopause zone in the Earth's atmosphere. It helps maintain pressure when stratocruising and protects the aircraft fro ...
increased its seating capacity to 180 passengers in a two-class and up to 220 passengers in a one-class configuration. The -900ER partly closed the gap left by the discontinuation of the Boeing 757-200, and directly competes with the
Airbus A321 The Airbus A321 is a member of the Airbus A320 family of short to medium range, Narrow-body aircraft, narrow-body, commercial passenger Twinjet, twin engine jet airliners; it carries 185 to 236 passengers. It has a stretched fuselage which was ...
.


737 MAX (fourth generation)

The ''Boeing 737 MAX'' is the name given to the main models 737 MAX 7/8/9/10 series and the higher-density MAX 200 variant of the Boeing 737 family. It is offered in four main variants, typically offering 138 to 230 seats and a range of . The 737 MAX 7, MAX 8 (including the denser, 200-seat MAX 200), and MAX 9 replace the 737-700, -800, and -900 respectively. The further stretched 737 MAX 10 has also been added to the series. The aim was to re-engine the 737NG family using CFM LEAP-1B engines having very high bypass ratio, to compete with the
Airbus A320neo The Airbus A320neo family is an incremental development of the A320 family of narrow-body airliners produced by Airbus. The A320neo family (''neo'' being Greek for "new", as well as an acronym for "new engine option") is based on the Airbus A3 ...
family. On July 20, 2011, Boeing announced plans for a third major upgrade and respectively fourth generation of 737 series to be powered by the CFM LEAP-1B engine, with
American Airlines American Airlines, Inc. is a major airlines of the United States, major airline in the United States headquartered in Fort Worth, Texas, within the Dallas–Fort Worth metroplex, and is the Largest airlines in the world, largest airline in the ...
intending to order 100 of these aircraft. On August 30, 2011, Boeing confirmed the launch of the 737 new engine variant, to be called the
Boeing 737 MAX The Boeing 737 MAX is a series of narrow-body aircraft developed by Boeing Commercial Airplanes as the fourth generation of the Boeing 737. It succeeds the Boeing 737 Next Generation and incorporates more efficient CFM International LEAP engin ...
. It was based on earlier 737 designs with more efficient LEAP-1B power plants, aerodynamic improvements (most notably split-tip
winglets Wingtip devices are intended to improve the efficiency of fixed-wing aircraft by reducing drag. Although there are several types of wing tip devices which function in different manners, their intended effect is always to reduce an aircraft ...
), and airframe modifications. It competes with the
Airbus A320neo family The Airbus A320neo family is an incremental development of the A320 family of narrow-body airliners produced by Airbus. The A320neo family (''neo'' being Greek for "new", as well as an acronym for "new engine option") is based on the enhanc ...
that was launched in December 2010 and reached 1,029 orders by June 2011, breaking Boeing's monopoly with
American Airlines American Airlines, Inc. is a major airlines of the United States, major airline in the United States headquartered in Fort Worth, Texas, within the Dallas–Fort Worth metroplex, and is the Largest airlines in the world, largest airline in the ...
, which had an order for 130 A320neos that July. The 737 MAX had its first flight on January 29, 2016, and gained FAA certification on March 8, 2017. The first delivery was a MAX 8 on May 6, 2017, to Lion Air's subsidiary
Malindo Air Batik Air Malaysia (formerly known as Malindo Air) is a Malaysian full-service airline and a subsidiary of Indonesia's Lion Air Group. Headquartered in Ara Damansara, Petaling Jaya, Selangor, the airline operates domestic and international fligh ...
, which put it into service on May 22, 2017. , the series has received 5,011 firm orders. In March 2019, civil aviation authorities around the world grounded the 737 MAX following two
hull loss A hull loss is an aviation accident that damages the aircraft beyond economic repair, resulting in a total loss. The term also applies to situations where the aircraft is missing, the search for its wreckage is terminated, or the wreckage is ...
crashes which caused 346 deaths. On December 16, 2019, Boeing announced that it would suspend production of the 737 MAX from January 2020, which was resumed in May 2020. In the midyear 2020, the FAA and Boeing conducted a series of recertification test flights. On November 18, 2020, the FAA cleared the MAX to return to service. Before the aircraft can fly again, repairs must be implemented and airlines' training programs must be approved. Passenger flights in the U.S. are expected to resume before the end of the year. Worldwide, the first airline to resume passenger service was Brazilian low-cost Gol, on December 9, 2020.


737 MAX 7

The 737 MAX 7, a shortened variant of the MAX 8, was originally based on the 737-700, flying farther and accommodating two more seat rows at 18% lower fuel costs per seat. The redesign uses the 737-8 wing and landing gear; a pair of over-wing exits rather than the single-door configuration; a aft fuselage and a longer forward fuselage; structural re-gauging and strengthening; and systems and interior modifications to accommodate the longer length. Entry into service with launch operator Southwest Airlines was originally expected in January 2019, but certification delays have pushed this back, with Boeing CEO David Calhoun saying certification was possible in the first half of 2025. The 737 MAX 7 replaced the 737-700 and was predicted to carry 12 more passengers and fly farther than the competing
Airbus A319neo The Airbus A320neo family is an incremental development of the A320 family of narrow-body airliners produced by Airbus. The A320neo family (''neo'' being Greek for "new", as well as an acronym for "new engine option") is based on the enhanc ...
with 7% lower operating costs per seat.


737 MAX 8

The 737 MAX 8, the first variant of the 737 MAX, has a longer fuselage than the MAX 7. On July 23, 2013, Boeing completed the firm configuration for the 737 MAX 8. Its first commercial flight was operated by
Malindo Air Batik Air Malaysia (formerly known as Malindo Air) is a Malaysian full-service airline and a subsidiary of Indonesia's Lion Air Group. Headquartered in Ara Damansara, Petaling Jaya, Selangor, the airline operates domestic and international fligh ...
on May 22, 2017. The MAX 8 replaced the 737-800 and competed with the A320neo. The ''737 MAX 200'', a high-density version of the 737 MAX 8, was launched in September 2014 and named for seating for up to 200 passengers in a single-class layout with slimline seats requiring an extra pair of exit doors. The MAX 200 would be 20% more cost-efficient per seat, including 5% lower operating costs than the MAX 8 and would be the most efficient narrow-body on the market when entering service. In mid-November 2018, the first MAX 200 of the 135 ordered by Ryanair rolled out, in a 197-seat configuration. It was first flown from Renton on January 13, 2019, and was due to enter service in April 2019.


737 MAX 9

The 737 MAX 9, the stretched variant of the MAX 8, was launched with an order of 201 aircraft in February 2012. It made its roll-out on March 7, 2017, and first flight on April 13, 2017; It was certified by February 2018. The launch customer, Lion Air Group, took the first MAX 9 on March 21, 2018, before entering service with Thai Lion Air. The 737 MAX 9 replaced the 737-900 and competes with the
Airbus A321neo The Airbus A321neo is a Single-aisle aircraft, single-aisle airliner created by Airbus. The A321neo (''neo'' being an acronym for "new engine option") is developed from the Airbus A321 and Airbus A320neo family. It is the longest stretched fusela ...
.


737 MAX 10

The 737 MAX 10 was proposed as a stretched MAX 9 in mid-2016, enabling seating for 230 in a single class or 189 in two-class layout, compared to 193 in two-class seating for the A321neo. The modest stretch of fuselage enables the MAX 10 to retain the existing wing and CFM Leap 1B engine from the MAX 9 with a trailing-link main landing gear as the only major change. The MAX 10 was launched on June 19, 2017, with 240 orders and commitments from more than ten customers. The variant configuration with a predicted 5% lower trip cost and seat cost compared to the A321neo was firmed up by February 2018, and by mid-2018, the critical design review was completed. The MAX 10 has a similar capacity to the A321XLR, but shorter range and much poorer field performance in smaller airports. It was unveiled in Boeing's Renton factory on November 22, 2019, and first flew on June 18, 2021. The MAX 10 is still awaiting certification, with Boeing CEO David Calhoun saying in July 2024 that the MAX 10 could be certified in the first half of 2025. In the late 2010s, Boeing worked on a medium-range
Boeing New Midsize Airplane The New Midsize Airplane (NMA), or New Midsize Aircraft, (culturally referred to as the Boeing 797) is a concept airliner proposed by Boeing to fill the middle of the market segment. In 2015, Boeing determined the market was large enough to la ...
(NMA) with two variants seating 225 or 275 passengers and targeting the same market segment as the 737 MAX 10 and the Airbus A321neo. A Future Small Airplane (FSA) was also touted during this period. The NMA project was set aside in January 2020, as Boeing focused on returning the 737 MAX to service and announced that it would be taking a new approach to future projects.


Design

The 737 continued to evolve into many variants but still remains recognizable as the 737. These are divided into four generations but all are based on the same basic design.


Airframe

The fuselage cross section and nose are derived from that of the
Boeing 707 The Boeing 707 is an early American long-range Narrow-body aircraft, narrow-body airliner, the first jetliner developed and produced by Boeing Commercial Airplanes. Developed from the Boeing 367-80 prototype, the initial first flew on Decembe ...
and
Boeing 727 The Boeing 727 is an American Narrow-body aircraft, narrow-body airliner that was developed and produced by Boeing Commercial Airplanes. After the heavier Boeing 707, 707 quad-jet was introduced in 1958, Boeing addressed the demand for shorter ...
. Early 737 cockpits also inherited the "eyebrow windows" positioned above the main glareshield, which were a feature of the original 707 and 727 to allow for better crew visibility. Contrary to popular belief, these windows were not intended for
celestial navigation Celestial navigation, also known as astronavigation, is the practice of position fixing using stars and other celestial bodies that enables a navigator to accurately determine their actual current physical position in space or on the surface ...
(only the military T-43A had a sextant port for star navigation, which the civilian models lacked.) With modern avionics, the windows became redundant, and many pilots placed newspapers or other objects in them to block out sun glare. They were eliminated from the 737 cockpit design in 2004, although they are still installed on customer request. The eyebrow windows were sometimes removed and plugged, usually during maintenance overhauls, and can be distinguished by the metal plug which differs from the smooth metal in later aircraft that were not originally fitted with the windows. The 737 was designed to sit relatively low to the ground to accommodate the design of smaller airports in the late 1960s which often lacked jetbridges or motorized belt loaders. The low fuselage allowed passengers to easily board from a mobile stairway or
airstair An airstair is a set of steps built into an aircraft so that passengers may board and alight the aircraft. The stairs are often built into a clamshell-style door on the aircraft. Airstairs eliminate the need for passengers to use a Ground s ...
s (which are still available as an option on the 737 MAX) and for luggage to be hand-lifted into the cargo holds. However, the design has proved to be an issue as the 737 has been modernized with larger and more fuel efficient engines. The 737's main landing gear, under the wings at mid-cabin, rotates into wheel wells in the aircraft's belly. The legs are covered by partial doors, and "brush-like" seals aerodynamically smooth (or "fair") the wheels in the wells. The sides of the tires are exposed to the air in flight. "Hub caps" complete the aerodynamic profile of the wheels. It is forbidden to operate without the caps, because they are linked to the ground speed sensor that interfaces with the anti-skid brake system. The dark circles of the tires are clearly visible when a 737 takes off, or is at low altitude. From July 2008, the steel landing gear
brake A brake is a machine, mechanical device that inhibits motion by absorbing energy from a moving system. It is used for Acceleration, slowing or stopping a moving vehicle, wheel, axle, or to prevent its motion, most often accomplished by means of ...
s on new NGs were replaced by Messier-Bugatti carbon brakes, achieving weight savings to depending on whether standard or high-capacity brakes were equipped.Volkmann, Kelsey
"Boeing gets OK for new carbon brakes."
''St. Louis Business Journal'' via ''bizjournals.com.'' Retrieved: April 22, 2010.
On a 737-800 this gives a 0.5% improvement in fuel efficiency. 737s are not equipped with fuel dump systems. The original design was too small to require this, and adding a fuel dump system to the later, larger variants would have incurred a large weight penalty. Boeing instead demonstrated an "equivalent level of safety". Depending on the nature of the emergency, 737s either circle to burn off fuel or land overweight. If the latter is the case, the aircraft must be inspected by maintenance personnel for damage before being returned to service. File:Boeing 737-200 planform view.jpg, Original 737 with JT8D engines that span the entire wing chord File:Transaero b737-400 planform ei-cxk arp.jpg, 737 Classic with larger CFM56 engines mounted mostly ahead of the wing File:American Boeing 737-800 N886NN planform.jpg, alt=The 737NG with improved CFM56-7 engines and redesigned larger wing,
737 Next Generation The Boeing 737 Next Generation, commonly abbreviated as 737NG, or 737 Next Gen, is a twinjet, twin-engine narrow-body aircraft produced by Boeing Commercial Airplanes. Launched in 1993 as the third-generation derivative of the Boeing 737, it ha ...
with improved CFM56-7 engines and redesigned wing File:United Boeing 737-8 MAX N17322 planform.jpg,
737 MAX The Boeing 737 MAX is a series of narrow-body aircraft developed by Boeing Commercial Airplanes as the fourth generation of the Boeing 737. It succeeds the Boeing 737 Next Generation and incorporates more efficient CFM International LEAP engi ...
with larger CFM LEAP engines, mounted even further ahead of the wing


Cabin

The first generation Original series 737 cabin was replaced for the second generation Classic series with a design based on the
Boeing 757 The Boeing 757 is an American Narrow-body aircraft, narrow-body airliner designed and built by Boeing Commercial Airplanes. The then-named 7N7, a twinjet successor for the trijet Boeing 727, 727, received its first orders in August 1978. The ...
cabin. The Classic cabin was then redesigned once more for the third, Next Generation, 737 with a design based on the
Boeing 777 The Boeing 777, commonly referred to as the Triple Seven, is an American long-range wide-body airliner developed and manufactured by Boeing Commercial Airplanes. The 777 is the world's largest twinjet and the most-built wide-body airliner. ...
cabin. Boeing later offered the redesigned Sky Interior on the NG. The principal features of the Sky Interior include sculpted sidewalls, redesigned window housings, increased headroom and LED mood lighting,Kingsley-Jones, Max
"Narrow margins: Airbus and Boeing face pressure with the A-320 and 737."
''flightglobal.com'', October 27, 2009. Retrieved: June 23, 2010.
"Check Out Boeing's Swanky New High-Tech Interior."
''businessinsider.com.'' Retrieved: November 1, 2011.
larger pivot-bins based on the 777 and 787 designs and generally more luggage space, and claims to have improved cabin noise levels by 2–4 dB. The first 737 equipped Boeing Sky Interior was delivered to Flydubai in late 2010. Continental Airlines,
Alaska Airlines Alaska Airlines is a major American airline headquartered in SeaTac, Washington, within the Seattle metropolitan area. It is the fifth-largest airline in North America when measured by scheduled passengers carried, as of 2024. Alaska, togethe ...
,
Malaysia Airlines Malaysia Airlines ( Malay: ''Penerbangan Malaysia'') is the flag carrier of Malaysia, headquartered at Kuala Lumpur International Airport. The airline flies to destinations across Europe, Oceania and Asia from its main hub at Kuala Lumpur Int ...
, and TUIFly have also received Sky Interior-equipped 737s. File:Lufthansa 737 interior.jpg, 737 Classic interior File:Delta Air Lines Boeing 737-800 cabin.jpg, 737 Next Generation standard interior File:Norwegian Boeing 737-800 cabin Sky Interior.JPG, 737 Next Generation Sky Interior with pivot bins and LED lighting


Cockpit

The 737 uses a hydro-mechanical flight control system, similar to the Boeing 707 and typical of the period in which the 737 was originally designed. Pilot commands are transmitted to hydraulic boosters attached to the control surfaces via steel cables that run through the fuselage and wings, rather than by the electrical
fly-by-wire Fly-by-wire (FBW) is a system that replaces the conventional aircraft flight control system#Hydro-mechanical, manual flight controls of an aircraft with an electronic interface. The movements of flight controls are converted to electronic sig ...
systems found in more recent designs like the Airbus A320 or Boeing 777. The primary flight controls have mechanical backups. In the event of total hydraulic system failure or double engine failure, they will automatically revert to control via
servo tab A servo tab is a small hinged device installed on an aircraft control surface to assist the movement of the Flight control surfaces, control surfaces. Introduced by the German firm Flettner, servo tabs were formerly known as Flettner tabs. Ser ...
. In this mode, termed ''manual reversion'', the servo tabs aerodynamically control the elevators and ailerons; these servo tabs are in turn controlled by cables running to the control yoke. The pilot's muscle forces alone control the tabs. The 737 Next Generation series introduced a six-screen
LCD A liquid-crystal display (LCD) is a flat-panel display or other electronically modulated optical device that uses the light-modulating properties of liquid crystals combined with polarizers to display information. Liquid crystals do not em ...
glass cockpit A glass cockpit is an aircraft cockpit that features an array of electronic (digital) flight instrument display device, displays, typically large liquid-crystal display, LCD screens, rather than traditional Analog device, analog dials and gauges ...
with modern avionics but designed to retain crew commonality with previous 737 generations. The 737 MAX introduced a 4 15.1 inch landscape LCD screen cockpit manufactured by
Rockwell Collins Rockwell Collins, Inc. was a multinational corporation headquartered in Cedar Rapids, Iowa, providing avionics and information technology systems and services to government agencies and aircraft manufacturers. It was formed when the Collins Radi ...
derived from the
Boeing 787 Dreamliner The Boeing 787 Dreamliner is an American wide-body airliner developed and manufactured by Boeing Commercial Airplanes. After dropping its unconventional Sonic Cruiser project, Boeing announced the conventional 7E7 on January 29, 2003, wh ...
. Except for the spoilers, which are fly-by-wire controlled, and all the analog instruments, which became digital, everything else is similar to the cockpits of the previous 737 generations to maintain commonality. File:Boeing 737-2V6 Advanced Cockpit Dubai Air Show Ryabtsev.jpg, Original 737 cockpit File:Cockpit of 737-300 LN-KKU.jpg, 737 Classic cockpit File:S7 Airlines Boeing 737-8ZS flight deck Beltyukov.jpg, 737 Next Generation cockpit File:737 Max Cockpit.jpg, 737 MAX cockpit


Engines

Engines on the 737 Classic series (-300, -400, -500) and Next-Generation series (-600, -700, -800, -900) do not have circular inlets like most aircraft but rather a planform on the lower side, which has been dictated largely by the need to accommodate ever larger engine diameters. The 737 Classic series featured CFM56 high bypass
turbofan A turbofan or fanjet is a type of airbreathing jet engine that is widely used in aircraft engine, aircraft propulsion. The word "turbofan" is a combination of references to the preceding generation engine technology of the turbojet and the add ...
engines, which were 25% more efficient and also reduced noise significantly over JT8D low bypass engines used on the 737 Original series (-100 and -200), but also posed an engineering challenge given the low ground clearance of the Boeing 737 family. Boeing and engine supplier
CFM International CFM International is a Franco-American aircraft engine manufacturer. The company is a joint venture between GE Aerospace and Safran Aircraft Engines (formerly known as Snecma) and is headquartered in Cincinnati, Ohio. It was founded in 1974 to bu ...
(CFMI) solved the problem by placing the engine ahead of (rather than below) the wing, and by moving engine accessories to the sides (rather than the bottom) of the engine pod, giving the 737 Classic and later generations a distinctive non-circular air intake. The improved, higher pressure ratio CFM56-7 turbofan engine on the 737 Next Generation is 7% more fuel-efficient than the previous CFM56-3 on the 737 Classic with the same bypass ratio. The newest 737 variants, the 737 MAX series, feature LEAP-1B engines from CFMI with a fan diameter. These engines were expected to be 10-12% more efficient than the CFM56-7B engines on the 737 Next Generation series. File:Boeing 737-200 (Brasilia Air Base) JT8D.jpg, Original 737 with JT8D engine mounted under the wing with original cowling design File:Boeing 737-524.jpg, 737 Classic with larger CFM56 engine mounted mostly ahead of the wing with an ovoid "hamster pouch" inlet with a flattened bottom File:CFM-56 Lauda 737.jpg, 737 Next Generation with CFM56-7 engine with a more rounded inlet due to a redesigned fan in the engine File:Boeing 737-9 MAX CFM LEAP-1B PAS.jpg, 737 MAX with larger CFM LEAP engines, mounted even further ahead of the wing a nacelle with chevrons


Wingtips

The Original -100 and -200 series were built without
wingtip devices A wing tip (or wingtip) is the part of the wing that is most distant from the fuselage of a fixed-wing aircraft. Because the wing tip shape influences the size and Drag (physics), drag of the wingtip vortices, tip design has produced a d ...
, but these were later introduced to improve fuel efficiency. The 737 has evolved four winglet types: the 737-200 Mini-winglet, 737 Classic/NG Blended Winglet, 737 Split Scimitar Winglet, and 737 MAX Advanced Technology Winglet. The 737-200 Mini-winglets are part of the Quiet Wing Corp modification kit that received certification in 2005. Blended winglets were standard on the 737 NG since 2000 and are available for retrofit on 737 Classic models. These winglets stand approximately tall and are installed at the wing tips. They improve fuel efficiency by up to 5% through lift-induced drag reduction achieved by moderating
wingtip vortices Wingtip vortices are circular patterns of rotating air left behind a wing as it generates Lift (force), lift. The name is a misnomer because the cores of the vortex, vortices are slightly inboard of the wing tips. Wingtip vortices are sometimes ...
. Split Scimitar winglets became available in 2014 for the 737-800, 737-900ER, BBJ2 and BBJ3, and in 2015 for the 737-700, 737-900 and BBJ1. Split Scimitar winglets were developed by Aviation Partners, the same Seattle-based corporation that developed the blended winglets; the Split Scimitar winglets produce up to a 5.5% fuel savings per aircraft compared to 3.3% savings for the blended winglets. Southwest Airlines flew their first flight of a 737-800 with Split Scimitar winglets on April 14, 2014. The next generation 737, 737 MAX, will feature an Advanced Technology (AT) Winglet that is produced by Boeing. The Boeing AT Winglet resembles a cross between the Blended Winglet and the Split Scimitar Winglet. An optional Enhanced Short Runway Package was developed for use on short runways. File:2011-05-19-flughafen-erfurt-by-RalfR-43 737 Air Berlin.jpg, Blended Winglet, standard on 737 Next Generation, a retrofit option for Classics File:B737-800 Split Winglet WP 20141110 001.jpg, Split Scimitar Winglet standard on later 737 Next Generation models File:Boeing 737 MAX (23326959580) winglet.jpg, Advanced Technology Winglet standard on MAX


Other variants


737 AEW&C

The
Boeing 737 AEW&C The Boeing E-7 Wedgetail, also marketed as the Boeing 737 AEW&C, is a twin-engine airborne early warning and control aircraft based on the Boeing 737 Next Generation design. It has a fixed, active electronically scanned array radar antenna inst ...
is a 737-700IGW roughly similar to the 737-700ER. This is an
Airborne Early Warning and Control An airborne early warning and control (AEW&C) system is an airborne radar early warning system designed to detect aircraft, ships, vehicles, missiles and other incoming projectiles at long ranges, as well as performing command and control of the ...
(AEW&C) version of the 737NG.
Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...
is the first customer (as Project Wedgetail), followed by
Turkey Turkey, officially the Republic of Türkiye, is a country mainly located in Anatolia in West Asia, with a relatively small part called East Thrace in Southeast Europe. It borders the Black Sea to the north; Georgia (country), Georgia, Armen ...
and South Korea.


T-43/CT-43A

The T-43 was a 737-200 modified for use by the
United States Air Force The United States Air Force (USAF) is the Air force, air service branch of the United States Department of Defense. It is one of the six United States Armed Forces and one of the eight uniformed services of the United States. Tracing its ori ...
for training navigators, now known as USAF combat systems officers. Informally referred to as the ''Gator'' (an abbreviation of "navigator") and "Flying Classroom", nineteen of these aircraft were delivered to the
Air Training Command The Air Training Command (ATC) is a former United States Air Force (USAF) Major Command designation. It was headquartered at Randolph Air Force Base, Texas, but was initially formed at Barksdale Air Force Base, Louisiana. It was re-designated ...
at Mather AFB, California during 1973 and 1974. Two additional aircraft were delivered to the Colorado Air National Guard at Buckley ANGB (later
Buckley AFB Buckley Space Force Base is a United States Space Force base in Aurora, Colorado named after United States Army Air Service First lieutenant, First Lieutenant John Harold Buckley. The base is run by Space Base Delta 2, with major units includin ...
) and Peterson AFB, Colorado, in direct support of cadet air navigation training at the nearby U.S. Air Force Academy. Two T-43s were later converted to CT-43As, similar to the CT-40A Clipper below, in the early 1990s and transferred to
Air Mobility Command The Air Mobility Command (AMC) is a List of Major Commands of the United States Air Force, Major Command (MAJCOM) of the United States Air Force, U.S. Air Force. It is headquartered at Scott Air Force Base, Illinois, east of St. Louis, Missouri, ...
and
United States Air Forces in Europe United may refer to: Places * United, Pennsylvania, an unincorporated community * United, West Virginia, an unincorporated community Arts and entertainment Films * ''United'' (2003 film), a Norwegian film * ''United'' (2011 film), a BBC Two f ...
, respectively, as executive transports. A third aircraft was also transferred to
Air Force Materiel Command The Air Force Materiel Command (AFMC) is a Major Command (MAJCOM) of the United States Air Force (USAF). AFMC was created on July 1, 1992, through the amalgamation of the former Air Force Logistics Command (AFLC) and the former Air Force System ...
for use as a radar test bed aircraft and was redesignated as an NT-43A. The T-43 was retired by the
Air Education and Training Command The Air Education and Training Command (AETC) is one of the nine List of major commands of the United States Air Force, Major Commands (MAJCOM) of the United States Air Force (USAF), reporting to Headquarters, United States Air Force. It was esta ...
in 2010 after 37 years of service.


C-40 Clipper

The Boeing C-40 Clipper is a military version of the 737-700C NG. It is used by both the
United States Navy The United States Navy (USN) is the naval warfare, maritime military branch, service branch of the United States Department of Defense. It is the world's most powerful navy with the largest Displacement (ship), displacement, at 4.5 millio ...
and the
United States Air Force The United States Air Force (USAF) is the Air force, air service branch of the United States Department of Defense. It is one of the six United States Armed Forces and one of the eight uniformed services of the United States. Tracing its ori ...
, and has been ordered by the
United States Marine Corps The United States Marine Corps (USMC), also referred to as the United States Marines or simply the Marines, is the maritime land force service branch of the United States Department of Defense. It is responsible for conducting expeditionar ...
. Technically, only the Navy C-40A variant is named "Clipper", whereas the USAF C-40B/C variants are officially unnamed.


P-8 Poseidon

The
P-8 Poseidon The Boeing P-8 Poseidon is an American maritime patrol aircraft, maritime patrol and reconnaissance aircraft developed and produced by Boeing Defense, Space & Security. It was developed for the United States Navy as a derivative of the civilian ...
developed for the
United States Navy The United States Navy (USN) is the naval warfare, maritime military branch, service branch of the United States Department of Defense. It is the world's most powerful navy with the largest Displacement (ship), displacement, at 4.5 millio ...
by
Boeing Defense, Space & Security Boeing Defense, Space & Security (BDS) is a division of Boeing, the Boeing Company based in Arlington, Virginia, near Washington, D.C. The division builds military Military aircraft, airplanes, Military helicopter, rotorcraft, and Missile, missil ...
, based on the Next Generation 737-800ERX. The P-8 can be operated in the
anti-submarine warfare Anti-submarine warfare (ASW, or in the older form A/S) is a branch of underwater warfare that uses surface warships, aircraft, submarines, or other platforms, to find, track, and deter, damage, or destroy enemy submarines. Such operations ar ...
(ASW),
anti-surface warfare Anti-surface warfare (ASuW or ASUW) is the branch of naval warfare concerned with the suppression of surface combatants. More generally, it is any weapons, sensors, or operations intended to attack or limit the effectiveness of an adversary's ...
(ASUW), and shipping interdiction roles. It is armed with
torpedo A modern torpedo is an underwater ranged weapon launched above or below the water surface, self-propelled towards a target, with an explosive warhead designed to detonate either on contact with or in proximity to the target. Historically, such ...
es, Harpoon anti-ship missiles and other weapons, and is able to drop and monitor
sonobuoy A sonobuoy (a portmanteau of sonar and buoy) is a small expendable sonar buoy dropped from aircraft or ships for anti-submarine warfare or underwater acoustic research. Sonobuoys are typically around in diameter and long. When floating on t ...
s, as well as operate in conjunction with other assets such as the
Northrop Grumman MQ-4C Triton The Northrop Grumman MQ-4C Triton is an American high-altitude long endurance unmanned aerial vehicle (UAV) developed for and flown by the United States Navy and Royal Australian Air Force as a surveillance aircraft. Together with its associate ...
maritime surveillance
unmanned aerial vehicle An unmanned aerial vehicle (UAV) or unmanned aircraft system (UAS), commonly known as a drone, is an aircraft with no human pilot, crew, or passengers onboard, but rather is controlled remotely or is autonomous.De Gruyter Handbook of Dron ...
(UAV).


VC-96

The VC-96 designation was applied to two 737-2N3s operated by the
Brazilian Air Force The Brazilian Air Force (, FAB) is the air branch of the Brazilian Armed Forces and one of the three national uniformed services. The FAB was formed when the Brazilian Brazilian Army Aviation (1919–1941), Army and Brazilian Naval Aviation, Nav ...
's Special Transport Group (GTE).


Boeing Business Jet (BBJ)

In the late 1980s, Boeing marketed the 77-33 jet, a business jet version of the 737-300. The name was short-lived. After the introduction of the Next Generation series, Boeing introduced the Boeing Business Jet (BBJ) series. The BBJ1 was similar in dimensions to the 737-700 but had additional features, including stronger wings and landing gear from the 737-800, and had increased range over the other 737 models through the use of extra fuel tanks. The first BBJ rolled out on August 11, 1998, and flew for the first time on September 4. On October 11, 1999, Boeing launched the BBJ2. Based on the 737-800, it is longer than the BBJ1, with 25% more cabin space and twice the baggage space, but has slightly reduced range. It is also fitted with auxiliary belly fuel tanks and winglets. The first BBJ2 was delivered on February 28, 2001. Boeing's BBJ3 is based on the 737-900ER. The BBJ3 has of floor space, 35% more interior space, and 89% more luggage space than the BBJ2. It has an auxiliary fuel system, giving it a range of up to , and a
Head-up display A head-up display, or heads-up display, also known as a HUD () or head-up guidance system (HGS), is any transparent display that presents data without requiring users to look away from their usual viewpoints. The origin of the name stems from a ...
. Boeing completed the first example in August 2008. This aircraft's cabin is pressurized to a simulated altitude.


Boeing Converted Freighter program

The Boeing Converted Freighter program (BCF), or the 737-800BCF program, was launched by Boeing in 2016. It converts old 737-800 passenger jets to dedicated freighters. The first 737-800BCF was delivered in 2018 to GECAS, which is leased to West Atlantic. Boeing has signed an agreement with Chinese YTO Cargo Airlines to provide the airline with 737-800BCFs pending a planned program launch.


Experimental

Four 737 aircraft have been used in Boeing test programs. In 2012, a new 737-800 bound for American Airlines became the first ecoDemonstrator airframe in a program that continues annually into the 2020s. In conjunction with many industry partners, the program aims to reduce the
environmental impact of aviation Aircraft engines produce gases, noise, and particulates from fossil fuel combustion, raising environmental concerns over their global effects and their effects on local air quality. Jet airliners contribute to climate change by emitting ...
. In 2012 it tested the winglets which would eventually be used in the 737 MAX series. Testing also included a variable area exhaust nozzle, regenerative hydrogen
fuel cell A fuel cell is an electrochemical cell that converts the chemical energy of a fuel (often hydrogen fuel, hydrogen) and an oxidizing agent (often oxygen) into electricity through a pair of redox reactions. Fuel cells are different from most bat ...
s for electrical power, and sustainable aviation fuel (SAF). In 2018, one of the 737 MAX 7 prototypes participated in Boeing's Quiet Technology Demonstrator 3 (QTD3) program, in which a
NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...
engine inlet designed to reduce engine noise was tested over an acoustic array at Moses Lake, Washington. A 737 MAX 9 was used as the 2021 ecoDemonstrator. A new airframe in a special Alaska Airlines livery flew an extensive test program, a major part of which was the use of SAF in blends of up to 50% including a flight from Seattle to
Glasgow Glasgow is the Cities of Scotland, most populous city in Scotland, located on the banks of the River Clyde in Strathclyde, west central Scotland. It is the List of cities in the United Kingdom, third-most-populous city in the United Kingdom ...
,
Scotland Scotland is a Countries of the United Kingdom, country that is part of the United Kingdom. It contains nearly one-third of the United Kingdom's land area, consisting of the northern part of the island of Great Britain and more than 790 adjac ...
, to attend the United Nations COP26 Climate Change Conference. Other test areas included halon-free fire extinguisher (ground testing only), a low-profile anti-collision light, and text-based
air traffic control Air traffic control (ATC) is a service provided by ground-based air traffic controllers who direct aircraft on the ground and through a given section of controlled airspace, and can provide advisory services to aircraft in non-controlled air ...
communications. At the end of the testing the aircraft was returned to standard configuration, and was delivered to Alaska Airlines in 2022. During October 2023 a 737 MAX 10 destined for United Airlines flew a series of test flights to compare the emissions of SAF, including the contrails, with those of conventional fuel. The emissions were measured by NASA's
Douglas DC-8 The Douglas DC-8 (sometimes McDonnell Douglas DC-8) is an early long-range Narrow-body aircraft, narrow-body jetliner designed and produced by the American Douglas Aircraft Company. Work began in 1952 towards the United States Air Force's (USA ...
Airborne Science Lab which flew close behind the 737, which wore a special livery as part of a series of special tests named ecoDemonstrator Explorer.


Competition

The Boeing 737 Classic, Next Generation and MAX series have faced significant competition from the
Airbus A320 family The Airbus A320 family is a series of narrow-body airliners developed and produced by Airbus. The A320 was launched in March 1984, first flew on 22 February 1987, and was introduced in April 1988 by Air France. The first member of the fami ...
first introduced in 1988. The relatively recent
Airbus A220 The Airbus A220 is a family of five-abreast narrow-body airliners by Airbus Canada Limited Partnership (ACLP). It was originally developed by Bombardier Aviation and had two years in service as the Bombardier CSeries. The program was launche ...
family now also competes against the smaller capacity end of the 737 variants. The A320 was developed to compete also with the McDonnell Douglas MD-80/90 and 95 series; the 95 later becoming the
Boeing 717 The Boeing 717 is an American five-abreast narrow-body aircraft, narrow-body airliner produced by Boeing Commercial Airplanes. The Twinjet, twin-engine airliner was developed for the 100-seat market and originally marketed by McDonnell Dougla ...
. Since July 2017, Airbus had a 59.4% market share of the re-engined single aisle market, while Boeing had 40.6%; Boeing had doubts on over-ordered A320neos by new operators and expected to narrow the gap with replacements not already ordered. However, in July 2017, Airbus had still 1,350 more A320neo orders than Boeing had for the 737 MAX. Boeing delivered 8,918 of the 737 family between March 1988 and December 2018, while
Airbus Airbus SE ( ; ; ; ) is a Pan-European aerospace corporation. The company's primary business is the design and manufacturing of commercial aircraft but it also has separate Airbus Defence and Space, defence and space and Airbus Helicopters, he ...
delivered 8,605 A320 family aircraft over a similar period since first delivery in early 1988. * *


Operators

The five largest operators of the Boeing 737 are
Southwest Airlines Southwest Airlines Co., or simply Southwest, is a Major airlines of the United States, major airline in the United States that formerly operated on a low-cost carrier model. It is headquartered in the Love Field, Dallas, Love Field neighborhood ...
(815),
Ryanair Ryanair is an Irish Low-cost carrier#Ultra low-cost carrier, ultra low-cost airline group headquartered in Swords, County Dublin, Ireland. The parent company, Ryanair Holdings plc, includes subsidiaries Ryanair , Malta Air, Buzz (Ryanair), Buzz ...
(566),
United Airlines United Airlines, Inc. is a Major airlines of the United States, major airline in the United States headquartered in Chicago, Chicago, Illinois that operates an extensive domestic and international route network across the United States and six ...
(496),
American Airlines American Airlines, Inc. is a major airlines of the United States, major airline in the United States headquartered in Fort Worth, Texas, within the Dallas–Fort Worth metroplex, and is the Largest airlines in the world, largest airline in the ...
(363), and
Delta Air Lines Delta Air Lines, Inc. is a Major airlines of the United States, major airline in the United States headquartered in Atlanta, Georgia (U.S. state), Georgia, operating nine hubs, with Hartsfield–Jackson Atlanta International Airport being its ...
(240) as of June 2024.


Usage


Civilian

In 2006, over 4,500 Boeing 737s were operated by more than 500 airlines, flying to 1,200 destinations in 190 countries and on average 1,250 aircraft were airborne, with two either departing or landing every five seconds. The 737 was the most commonly flown aircraft in 2008, 2009, and 2010. In 2013, over 5,580 Boeing 737s were operated by more than 342 airlines in 111 countries, which represented more than 25% of the worldwide fleet of large jet airliners. The 737 had carried over 16.8 billion passengers (twice of 7.1 billion world population in that time) over 119 billion miles (192 billion km) with more than 184 million flights or 264 million hours in the air. In 2016, there were 6,512 Boeing 737 airliners in service (5,567 737NGs plus 945 737-200s and 737 Classics), more than the 6,510 Airbus A320 family. while in 2017, there were 6,858 737s in service (5,968 737NGs plus 890 737-200s and classics), fewer than the 6,965 A320 family. By 2018, over 7,500 Boeing 737s were in service and on average 2,800 aircraft were airborne, with two either departing or landing every three seconds, carrying around three million passengers daily. At the time, the global 737 fleet had carried over 22 billion passengers since its introduction. , there were 9,315 Boeing 737s in service, slightly fewer than the 9,353 of the A320 family, as more 737s were already out of service.


Military

Many countries operate the 737 passenger, BBJ, and cargo variants in government or military applications. Users with 737s include: * * * * * * * * * * * * * * * * * * * * * * * * * * *


Orders and deliveries


Orders

The 737 had the highest, cumulative orders for any airliner until surpassed by the A320 family in October 2019. In that year, 737 orders dropped by 90%, as 737 MAX orders dried up after the March grounding. The 737 MAX backlog fell by 182, mainly due to the Jet Airways bankruptcy, a drop in Boeing's airliner backlog was a first in at least the past 30 years. , 16,956 units of the Boeing 737 family had been ordered, with 4,864 orders were pending, or 4,433 when including "additional criteria for recognizing contracted backlog with customers beyond the existence of a firm contract" (ASC 606 Adjustment).


Deliveries

Boeing delivered the 5,000th 737 to
Southwest Airlines Southwest Airlines Co., or simply Southwest, is a Major airlines of the United States, major airline in the United States that formerly operated on a low-cost carrier model. It is headquartered in the Love Field, Dallas, Love Field neighborhood ...
on February 13, 2006, the 6,000th 737 to
Norwegian Air Shuttle Norwegian Air Shuttle Aksjeselskap, ASA, trading as Norwegian, is a Norway, Norwegian Low-cost carrier, low-cost airline and Scandinavia's second-largest airline, behind Scandinavian Airlines. It is the fourth largest low-cost carrier in Europe ...
in April 2009, the 7,000th 737 to Flydubai on December 16, 2011, the 8,000th 737 to
United Airlines United Airlines, Inc. is a Major airlines of the United States, major airline in the United States headquartered in Chicago, Chicago, Illinois that operates an extensive domestic and international route network across the United States and six ...
on April 16, 2014, and the 9,000th 737 to China United Airlines in April 2016. The 10,000th 737 was ordered in July 2012, rolled out on March 13, 2018, and was to be delivered to Southwest Airlines; the backlog at the time stood at over 4,600 aircraft. , 12,092 units of the Boeing 737 family had been delivered, while 12,054 of the competing A320 family had been delivered. Therefore, the 737 is the most delivered jetliner.


Model summary


Accidents and incidents

, the Boeing 737 family has been involved in 529
aviation accidents and incidents An aviation accident is an event during aircraft operation that results serious injury, death, or significant destruction. An aviation incident is any operating event that compromises safety but does not escalate into an aviation accident. Pre ...
, including 215
hull loss A hull loss is an aviation accident that damages the aircraft beyond economic repair, resulting in a total loss. The term also applies to situations where the aircraft is missing, the search for its wreckage is terminated, or the wreckage is ...
accidents out of 234 hull-losses, resulting in a total of 5,779 fatalities. A Boeing analysis of commercial jet airplane accidents between 1959 and 2013 found that the hull loss rate for the Original series was 1.75 per million departures, for the Classic series 0.54, and the Next Generation series 0.27. As of 2023, the analysis showed that the hull loss rate for the Original series was 1.78 (0.87 fatal hull loss rate), for the Classic series 0.81 (0.26 fatal hull loss rate), for the Next Generation series 0.18 (0.04 fatal hull loss rate), and for the MAX series 1.48 (1.48 fatal hull loss rate) per million departures. During the 1990s, a series of rudder issues on series -200 and -300 aircraft resulted in multiple incidents. In two total loss accidents, United Airlines Flight 585 (a -200 series) and USAir Flight 427, (a -300), the pilots lost control of the aircraft following a sudden and unexpected deflection of the
rudder A rudder is a primary control surface used to steer a ship, boat, submarine, hovercraft, airship, or other vehicle that moves through a fluid medium (usually air or water). On an airplane, the rudder is used primarily to counter adverse yaw ...
, killing everyone aboard, a total of 157 people. Similar rudder issues led to a temporary loss of control on at least five other 737 flights before the problem was ultimately identified. The
National Transportation Safety Board The National Transportation Safety Board (NTSB) is an independent U.S. government investigative agency responsible for civil transportation accident investigation. In this role, the NTSB investigates and reports on aviation accidents and inci ...
determined that the accidents and incidents were the result of a design flaw that could result in an uncommanded movement of the aircraft's rudder. As a result of the NTSB's findings, the
Federal Aviation Administration The Federal Aviation Administration (FAA) is a Federal government of the United States, U.S. federal government agency within the United States Department of Transportation, U.S. Department of Transportation that regulates civil aviation in t ...
ordered that the rudder servo valves be replaced on all 737s and mandated new training protocols for pilots to handle an unexpected movement of control surfaces. Following the crashes of two 737 MAX 8 aircraft, Lion Air Flight 610 in October 2018 and Ethiopian Airlines Flight 302 in March 2019, which caused 346 deaths, civil aviation authorities around the world grounded the 737 MAX series. On December 16, 2019, Boeing announced that it would suspend production of the 737 MAX from January 2020. Production of the MAX series resumed on May 27, 2020.


Aircraft on display

Owing to the 737's long production history and popularity, many older 737s have found use in museums after reaching the end of useful service. * 19437/1: 737-130 registered N515NA on static display at the
Museum of Flight The Museum of Flight is a private Nonprofit organization, non-profit Aircraft, air and Spacecraft, space museum in the Seattle metropolitan area. It is located at the southern end of Boeing Field, King County International Airport (Boeing Fi ...
in
Seattle, Washington Seattle ( ) is the List of municipalities in Washington, most populous city in the U.S. state of Washington (state), Washington and in the Pacific Northwest region of North America. With a population of 780,995 in 2024, it is the List of Unit ...
. It was the first 737 built and is painted in NASA markings. * 19047/14: 737-222 registered N9009U preserved by
Southern Illinois University Carbondale Southern Illinois University (SIU) is a public research university in Carbondale, Illinois, United States. Chartered in 1869, SIU is the oldest and flagship campus of the Southern Illinois University system. SIU enrolls students from all 50 sta ...
at Southern Illinois Airport. * 20213/160: 737-201 registered N213US forward fuselage on static display at the Museum of Flight in Seattle, Washington, in
USAir US Airways was a major airline in the United States. It was originally founded in Pittsburgh as a mail delivery airline called All American Aviation, which soon became a commercial passenger airline. In 1953, it was renamed Allegheny Airlines an ...
livery. * 20561/292: 737-281 registered LV-WTX on static display at the National Museum of Aeronautics in
Morón, Buenos Aires Morón () is a city in the Argentine province of Buenos Aires, capital of the Morón ''partido'', located in the Greater Buenos Aires metropolitan area, at . Located 20 km (13 mi) west of Downtown Buenos Aires, Morón i ...
. * 20562/293: 737-281 registered CC-CSK fuselage preserved at Motel Bahía in
Concón Concón is a Chilean city and commune in Valparaíso Province, Valparaíso Region. It is a major tourist center known for its beaches, ''balnearios'' (beachside resorts) and night life. Geography The commune of Concón spans an area of . It ...
,
Chile Chile, officially the Republic of Chile, is a country in western South America. It is the southernmost country in the world and the closest to Antarctica, stretching along a narrow strip of land between the Andes, Andes Mountains and the Paci ...
. * 21262/470: 737-2H4 registered C-GWJT on static display at the
British Columbia Institute of Technology The British Columbia Institute of Technology (also referred to as BCIT), is a public polytechnic institute in Burnaby, British Columbia, Canada. The technical institute has five campuses located in the Metro Vancouver region, with its main cam ...
Aerospace Technology Campus in
Richmond, British Columbia Richmond is a city in the coastal Lower Mainland region of British Columbia, Canada. Mainly a suburban city, it occupies almost the entirety of Lulu Island (excluding Queensborough, New Westminster, Queensborough), between the two estuarine dis ...
. It is used for ground instructional training. The aircraft was donated by WestJet and bears its livery. * 21340/499: 737-2H4 registered N29SW on static display at the Kansas Aviation Museum in
Wichita, Kansas Wichita ( ) is the List of cities in Kansas, most populous city in the U.S. state of Kansas and the county seat of Sedgwick County, Kansas, Sedgwick County. As of the 2020 United States census, 2020 census, the population of the city was 397, ...
. It was formerly operated by
Ryan International Airlines Ryan International Airlines, Inc. was an American FAR 121 airline with domestic, flag, and supplemental authority. Synopsis and history Based at Chicago Rockford International Airport in Rockford, Illinois, the US Postal Service was once the ...
and prior to that
Southwest Airlines Southwest Airlines Co., or simply Southwest, is a Major airlines of the United States, major airline in the United States that formerly operated on a low-cost carrier model. It is headquartered in the Love Field, Dallas, Love Field neighborhood ...
. * 21712/557: 737-275 registered C-GIPW preserved in operational condition at Alberta Flying Heritage Museum in Villeneuve,
Alberta Alberta is a Provinces and territories of Canada, province in Canada. It is a part of Western Canada and is one of the three Canadian Prairies, prairie provinces. Alberta is bordered by British Columbia to its west, Saskatchewan to its east, t ...
. Painted in
Pacific Western Airlines Pacific Western Airlines (PWA) was an airline that operated scheduled flights throughout western Canada and charter services around the world from the 1950s through the 1980s. In 1987, PWA purchased Canadian Pacific Air Lines, and the merged a ...
livery. * 22578/767: 737-290C registered N740AS on static display at the Alaska Aviation Heritage Museum in
Anchorage, Alaska Anchorage, officially the Municipality of Anchorage, is the List of cities in Alaska, most populous city in the U.S. state of Alaska. With a population of 291,247 at the 2020 United States census, 2020 census, it contains nearly 40 percent of ...
. It was formerly operated by
Alaska Airlines Alaska Airlines is a major American airline headquartered in SeaTac, Washington, within the Seattle metropolitan area. It is the fifth-largest airline in North America when measured by scheduled passengers carried, as of 2024. Alaska, togethe ...
. * 22826/878: 737-2H4 registered YV1361 preserved at a hotel in
Santiago Santiago (, ; ), also known as Santiago de Chile (), is the capital and largest city of Chile and one of the largest cities in the Americas. It is located in the country's central valley and is the center of the Santiago Metropolitan Regi ...
,
Chile Chile, officially the Republic of Chile, is a country in western South America. It is the southernmost country in the world and the closest to Antarctica, stretching along a narrow strip of land between the Andes, Andes Mountains and the Paci ...
. It was formerly operated by Avior Airlines. * 23059/980: 737-2Z6 registered 22–222 on static display at the
Royal Thai Air Force Museum The National Aviation Museum of the Royal Thai Air Force is located in Don Mueang District, Bangkok, Thailand. It is located on the Phahonyothin Road just to the south of Wing 6 of the domestic terminal of the Don Mueang International Airport, Don ...
in
Bangkok Bangkok, officially known in Thai language, Thai as Krung Thep Maha Nakhon and colloquially as Krung Thep, is the capital and most populous city of Thailand. The city occupies in the Chao Phraya River delta in central Thailand and has an estim ...
. * 22940/1037: 737-3H4 registered N300SW on static display at the Frontiers of Flight Museum in
Dallas, Texas Dallas () is a city in the U.S. state of Texas and the most populous city in the Dallas–Fort Worth metroplex, the List of Texas metropolitan areas, most populous metropolitan area in Texas and the Metropolitan statistical area, fourth-most ...
. It was the first such aircraft delivered to
Southwest Airlines Southwest Airlines Co., or simply Southwest, is a Major airlines of the United States, major airline in the United States that formerly operated on a low-cost carrier model. It is headquartered in the Love Field, Dallas, Love Field neighborhood ...
in November 1984. * 23257/1124: 737-301 registered PK-AWU on static display at ITE College Central in
Singapore Singapore, officially the Republic of Singapore, is an island country and city-state in Southeast Asia. The country's territory comprises one main island, 63 satellite islands and islets, and one outlying islet. It is about one degree ...
. * 23472/1194: 737-219 registered ZS-SMD on static display at the South African Airways Museum in
Germiston, Gauteng Germiston, also known as kwaDukathole, is a city in the East Rand region of Gauteng, South Africa, administratively forming part of the City of Ekurhuleni Metropolitan Municipality since the latter's establishment in 2000. It functions as the ...
. * 23660/1294: 737-377 registered G-CELS (nickname Elsie) on static display at Norwich International Aviation Academy, as an aircraft maintenance trainer. It is painted in the silver & red Jet2.com color scheme, without the logo branding. * 27286/2528: 737-3Q8 registered N759BA on static display at the
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in
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. It is painted in
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markings, and was previously operated by the airline as B-2921.


Specifications (Boeing 737-200 with JT8D-15A)


See also


References


Citations


Bibliography

* * * * * * * * * * *


External links


737 page on Boeing.com

The 737 Story on FlightInternational.com
* {{Authority control Aircraft first flown in 1967 737 Low-wing aircraft Twinjets 1960s United States airliners Aircraft with retractable tricycle landing gear