I thought there were limits on what a command spell could do?

Yeah, but in neither of the two animes (and the game as far as I know) really explore that.

Actually, if you do well with what you have, you can actually o gliding down with what's left of the momentum. I'm not very sure of the physic parts since I didn't get to learn about it but I did get told by one of my physic teachers that it's possible to keep gliding on air. He never explained why though.