as air fleet one thus e.g. designates the airplanes of an airline within the civilian range. the Lufthansa fleet etc.
One differentiates several kinds from air fleets:
in some states, like the USA, exist also still to atomic bomber fleets
the word air fleet became particularly in 2. Used on sides of the allied ones frequently, them their bomber formations, which attacked German cities, called world war often air fleets. Thus probably the British Air Force general Harris or also bomber Harris is considered as actual inventors of this word.