Not is you knew how it was done. I have one word for you. Wires! Thats for the one where he gets well off the ground. The one where he gets just a little bit off the ground is a wonderful illusion and evokes great responses from the spectators. Its an effect I rarely perform as the situations and conditions I normally perform in do not allow for such an illusion to be done properly or effectively.
I, being a magician and member of the International Brotherhood of Magicians can not divulge how stuff is done, but I have no problem letting out a secret here or there when justified.