Doesn't work. You try that, and a competent enemy will just bomb the airfields. Or hit them with SRBMs.
Fleet-in-being depends on harbors being safe. That just doesn't work in aerial warfare.
Sorry to disagree.
First thing, certainly the enemy can attack the air fleet while it's twiddling their thumbs. But, exactly the same applies to fleets, as you can see in Taranto, Pearl Harbor, Scapa Flow and Alexandria.
Note that two of those attacks weren't done from the air. Once you throw SRBMs in, there is no fleet in the world that can count its harbors as safe without actively patrolling wide areas around them, i.e., without having at least some of its assets (and some air assets) leaving port (and airfield).
Secondly, not all enemies are competent, or well-armed. The great example of an air fleet in being winning the war without even having to take off is the Luftwaffe when the Czechs gave up (I don't mean Munich, I mean for their final dismemberment). The main threat used against them was the bombing of their cities.
The Dutch also surrendered chiefly to the threat of city bombing, even though in that case the war was being waged, and since the Dutch were not speedy enough, a Luftwaffe unit was indeed sent to bomb Rotterdam. That makes it the cusp of the passage from air fleet in being to air fleet actually bombing, but had communications worked alright, the bombers would have been recalled. The objective had already been achieved (the Dutch had surrendered).
Thirdly, you are assuming a competent and well-armed enemy will always have the range to hit those airfields of the air fleet in being. That is not necessarily the case. The RAF simply did not deploy 95% of its bombers (and, even more importantly, its trainers) to an area within range of an
escorted attack by the Luftwaffe during the phony war. The French kept their few bomber units well away from the front line. These were air fleets in being (save for the fact that, for the British, it also was the seed of the 1,000-bomber raids of a few years later). And they did achieve their objective for some time: France and Britain suffered no city bombing for all the Phony War, and Britain for some time after that.