Thank you!
Fine-tuning the speed and having some sort of altitude control (whether diving or straight up/down) is definitely something I'll be doing if this ever starts turning into a proper game, rather than the demonstration of the generator it is at the moment. (Truth is, it's just a first-person controller for walking around on the surface, and flight is nothing more than the ability to turn gravity off.)
I'm curious why you'd want A & D swapped in flight. Vertical tilt I get -- I know that's very much a preference & I've just hard-coded what's right for me -- but I think it would be very strange to have the same control mean "walk left or fly right".