So you're able to fly.

The way it works is you somehow crank your metabolism WAY up. So you kill and regrow your cells way faster than usual. So you can just kinda move through the air by growing into a different place.

So you can do this, and hence fly. But by speeding up your metabolism so much you also age way faster. One day of flying uses up about one year of regular living. So you can fly, just by thinking about it, just like you always imagined it, but after a few weeks you're nearly dead from old age.

So you'd only fly to get up high. Then you'd fall. That way you'd save on the living. Fly as high as you can and then fall, just using the power to manoeuvre in and out of landing, in built up places and cities and mountains.