Flight calls are vocalisations made by

bird Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...

s in flight, often serving to keep flocks together.

References

Bird sounds {{Ornithology-stub