Criss Angel levitates the same way all other magicians do, by trick of the eye. There are things there that you are not looking at because he keeps you focused on him. Go to www.unexplained-mysteries.com for an explanation.
Levitation is an illusion. Magicians such as David Blaine, Cris Angel and others such as David Copperfield use tricks of the eye. Levitation is a well known trick of the eye in most cases where as in others case cables or even see through perspex may be used. With the lighting in the studios, trickery of the eye takes place where the carefully placed props or gimmicks may not be seen. In some cases mirrors have also being used to create a master illusion where somebody appears to levitate a human being in mid air. They are all tricks of the mind and eye and of course floating in mid really doesn't happen in real life. Please check out more levitating secrets from this street magic trick website. They cover most modern day methods of magic : http://street-magic-tricks.biz/David_Copperfield_LEVITATION_REVEALED._How_To_Do_It_X55563.html