Much of the magic you see on TV is not live. What you are viewing is from carefully calculated angles and shifts in the camera, such as in the instance of levitating. Usually the person being levitated wears a harness under his/her clothes and they are lifted by very thin wire against a very bright sky, to keep them out of view. Every once in a while you can catch shows on TV explaining how certain tricks are done, such as: levitating, making objects disappear, submersion in water for long periods of time, being decapitated, escaping restraints, etc. It's all a complex system of hiding your actions from view.
David Blane is all different kinds of strange, lol, but he is very amusing.