As a similar question, maybe appropriate here or maybe belonging to another thread all its own:
Ever hear of anyone who actually walked on water? Is that physically possible? Barefoot, that is...no floating aids whatsoever.
If so, then why not fly? Who says it hasn't been done but not advertised? There are a lot of individuals who have done incredible things but kept them to themselves.
I know if I had had some success in flight, I'm not sure I would advertise it. The explanations would be a bit too much trouble to go through.