Every time you take off, there's a pretty good chance that people nearby will notice. The government will want to study someone who has the ability to fly, so they'll start surveiling the area. Within a short time they'll figure out who you are, and you'll be captured and eventually dissected.
And, that's assuming your flight superpower comes with the ability to breathe at high altitudes, the ability to resist the cold you'd be exposed to by flying, the ability to see while flying without having your eyes dry out, etc.