Curious- are you talking about the idea of going prone on purpose in the air, or simply ignoring that part of the prone condition entirely?
Because a similar situation can happen if you are knocked prone while swimming.
I mostly bring this up because if the bullet point regarding ranged attacks is intended to reflect being prone on the ground, then there really should be a separate condition for other situations, like how a rider could be knocked prone, make their save to remain in the saddle, and be prone on the back of a horse, which I'm not sure should make you a harder target to hit or not (you haven't become a smaller target, though I suppose it's easier to hit the horse than the rider in such a situation).