If Copperfield levitates, then he can repeat the flight at any place and in any situation. Besides, as any actor, he has a temptation to fly not only over the scene but also in the auditorium. He does neither the first nor the second. They want to believe. However, the greatest thing is that Copperfield himself speakes only about his ability to fly, but not about levitation.
Superconductivity is a well known phenomenon among physicists.
If we cool a leaden cup down to the temperature of liquid helium, then place a regular magnet over it, the magnet will freely soar in the air. If you hide the superconductive cup under a table and do not tell anybody about it, then the magnet over the table will seem to be a real wonder. If, in addition, the cup is provided with controlling mechanisms for reciprocating motion, for moving the magnet up and down or inclining it in the air, then you can, at will and imperceptibly for others, control the motion of the magnet over the table. Superconductive cup with a magnet hanging over it. If you let a living being, for example a mouse, run on the table, then it will freely run between the hidden cup and the magnet.