An interceptor aircraft, or simply interceptor, is a type of fighter aircraft designed specifically for the defensive interception role against an attacking enemy aircraft, particularly bombers and reconnaissance aircraft. There are two general classes of interceptor: relatively lightweight aircraft built for high performance over short range, and heavier aircraft designed to fly at night or in adverse weather and operate over longer ranges.

For daytime operations, conventional fighters normally fill the interceptor role, as well as many other missions. Daytime interceptors have been used in a defensive role since the World War I era, but are perhaps best known from several major actions during World War II, notably the Battle of Britain where the Supermarine Spitfire and Hawker Hurricane developed a good reputation. Few aircraft can be considered dedicated daytime interceptors. Exceptions include the Messerschmitt Me 163B—the only rocket-powered, manned military aircraft ever to see combat—and to a lesser degree designs like the Mikoyan-Gurevich MiG-15, which had heavy armament specifically intended for anti-bomber missions.

Night fighters and bomber destroyers are, by definition, interceptors of the heavy type, although initially they were rarely referred to as such. In the early Cold War era the combination of jet-powered bombers and nuclear weapons created air force demand for highly capable interceptors; it is during this period that the term is perhaps most recognized and used. Examples of classic interceptors of this era include the F-106 Delta Dart, Sukhoi Su-15, and English Electric Lightning.

Through the 1960s and 1970s, the rapid improvements in design led to most air-superiority and multirole fighters, such as the Grumman F-14 Tomcat and McDonnell Douglas F-15 Eagle, having the performance to take on the point defense interception role, and the strategic threat moved from bombers to intercontinental ballistic missiles (ICBMs). Dedicated interceptor designs became rare, with the only widely used examples designed after the 1960s being the Tornado F3, Mikoyan MiG-25 "Foxbat", Mikoyan MiG-31 "Foxhound", and the Shenyang J-8 "Finback".

CF-100 Canuck prototypeSeveral other countries also introduced interceptor designs, although in the 1950s–1960s several planned interceptors never came to fruition, with the expectation that missiles would replace bombers.

The Argentine FMA I.Ae. 37 was a prototype jet fighter developed during the 1950s. It never flew and was cancelled in 1960.

The Canadian subsonic Avro Canada CF-100 Canuck served in numbers through 1950s. Its supersonic replacement, the CF-105 Arrow ("Avro Arrow"), was controversially cancelled in 1959.

The Swedish Saab 35 Draken was specifically designed for intercepting aircraft passing Swedish airspace at high altitudes in the event of a war between the Soviet Union and NATO. With the advent of low flying cruise-missiles and high-altitude AA-missiles the flight profile was changed, but regained the interceptor profile with the final version J 35J.

See also