Okay, um... my friend, who knows the series much better then I do, has offered a bit more of an explanation that will hopefully help.

[quote]I think you may have gotten confused by the animations error of having her stay in that one frame for too long. See, what Aoi is doing in the manga panel is teleporting in and teleporting back out in a matter of seconds. Aoi doesn't float, she controls her trajectory through her teleportation. This is makes it seem like she's floating in manga panels, but its more like a very controlled free fall. The thing is, like sometimes readers get confused, so do animators and that's what happened with that instance of her "floating" in the anime. If she could really fly, you would be able to see her do it very consistently, but most of the time she's either on the ground or teleport spamming is Kaoru isn't around to help her fly. Notably, Kaoru who can fly is almost never on the ground during confrontations because that's her ability, Aoi, however, never does that unless its her teleporting into the sky and using that teleportation to stay in the air.[/quote]