negative airaccelerate values accelerate the player in the air by just holding the movement key (though the direction is inverted, that means holding W will accelerate you backwards), somewhere around -1 is ok for a special day i think. demonstration:
Honestly, I'm not quite sure. As a special day this is kinda weak, On it's own I think it would work better as a round-modifier of sorts. You could combine this with something like a FF knife warday or tank day for more varied and chaotic movement.
During the creation of this thread my brain had increased it's electromagnetic activity to the point where i could control objects using my mind, I didn't need to use my arms anymore