I think this is a bit pedantic: if you create a fantasy world where every person can walk on air as easily as walking on land, it isn't magical to them, but it's still magical to us. It might not be what the game even defines as magic (susceptible to detect magic, dispel magic, anti-magic, etc.) but I think if you took the idea the on this planet everyone can effectively fly and asked anyone on the street, nobody would say that's "normal", no matter how normal it is to the inhabitants of that world.
We define fantasy (and to a degree, Sci-fi) by how different things are from what we expect, and as humans our base assumptions is something resembling Earth, complete with modern ideas of physics and biology. So, if you say that the people of your world walk on air, the first question is going to be "how?" You could say "they do, shut up" but that's not very engaging to the audience. You're asking them to suspend disbelief and aren't giving them a reason to. Now, you could argue its some weird genetic quirk that makes them buoyant in air, a strange effect of the world's gravity, a gift from the sky god, or everyone is descended from angelic beings and retain a single spark that allows airwalking, but no matter what you're doing, you are effectively saying "its magic" (or its sufficiently advanced technology, yada yada yada).
People who have anger management problems don't become highly resistant to mortal blows. People who study aestheticism and martial arts don't become immune to poison and disease or speak all known languages. Park rangers don't instictively know the type of number of every creature in a 1-mile radius. We explain that stuff by saying it's beyond normal human capabilities. Call it supernatural powers. Call it psionics. Call it mythic blood. Call it "magic and you ain't gotta explain $#!&" but you gotta explain it somehow, no matter how mundane it is to them, it's not to US and its our disbelief that needs suspending.
