Astramancer

I can fly at will. My proof is that I carry around a piece of paper on which I've written "yes, I can fly." If it helps, I've burned the edges to make it look old. If, for some reason, that isn't enough for you, then I won't show you that I can fly because you don't believe I can fly. If I trip, and you ask why I didn't just fly, then you must remember that I work in mysterious ways.