Footstool while YOU are airdodging?
Or to footstool someone who IS airdodging?
I assume the former, so nay.
However, if it had been footstool someone who is IN an airdodge, then I would say yes. That is, to have it actually affect them. Personally I think footstools should affect the footstooled regardless of what their animation is, it seems silly that nothing happens to them because they are doing an attack or w/e. Any other attacks/specials/grabs do not differentiate between the last frame of endlag on ftilt (or w/e the move is) and the first frame of idle after that, why should footstools? They are situational to land anyways and ordinarily you wouldn't be able to get that close to an opponent in the air in the first place without being able to hit them or without getting hit, so what exactly would be threatened to change? If anything it just does a little bit to open up some character's punishment game, it wouldn't have any effect on WHEN you can punish them. We can already footstool shielding opponents, at this point it kinda functions as an aerial grab that doesn't actually do damage, has awkward placing, and causes knockdown if airborne or nets you a hit of another move you could have landed from that position anyways.