Criss Angel stands at the edge of a tall building and holds his arms out. He begins to float, levitates over the edge of the building, and flies some distance before coming to light on another building.
Angel wears big, baggy clothes for a reason. In this case, the reason is that his body is wrapped with inner tubes that are filled with exactly enough helium to make his weight effectively zero. Because he is buoyant in the atmosphere, a little push off with the feet is enough to send Angel flying slowly through the air to his destination.
Note: This same effect was attempted in the 1930s by a German magician who made the mistakes of filling his apparatus with highly flammable hydrogen and attempting the flight while smoking. The resulting explosion was horrifically spectacular.
Note: Also, you shouldn't try this yourself because you will probably die.