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In military aviation, a wing is a unit of command. In most military aviation services, a wing is a relatively large formation of planes. In Commonwealth countries a wing usually comprises three squadrons, with several wings forming a group (around 10 squadrons). Each squadron will contain around 20 planes.

On its establishment in 1912, the British Royal Flying Corps (RFC) was intended to be an inter-service, combined force of the British Army and Royal Navy. Given the rivalry that existed between the army and navy, new terminology was used, in order to avoid marking the corps out as having an army or navy ethos. While the term "wing" had been used in the cavalry, its more general use predominated. Accordingly, the word "wing", with its allusion of flight, was chosen as the term of subdivision and the corps was split into a "Military Wing" (i.e. an army wing) and a "Naval Wing". Each wing consisted of a number of squadrons (the term "squadron" already being used by both the Army and the Navy).

By 1914, the naval wing had become the Royal Naval Air Service, and gained its independence from the Royal Flying Corps. In 1915, the Royal Flying Corps had significantly expanded and it was felt necessary to create organizational units which would control two or more squadrons; the term "wing" was re-used for these new organizational units.

The Royal Flying Corps was amalgamated with the Royal Naval Air Service in 1918, creating the Royal Air Force. The RFC usage of wing was maintained in the new service.

In most Commonwealth air forces, as well as some others, a wing is usually made up of three or four squadrons. In these air forces a wing is inferior to a group. Originally all wings were usually commanded by a wing commander (equivalent to a lieutenant colonel). From World War II onwards, operational flying wings have usually been commanded by group captains (equivalent to colonels), whereas ground-based wings have continued to be commanded by wing commanders.

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