In season 4, William usually levitates before jumping into the Digital Sea or when he activates a tower for X.A.N.A. In season 3, he only levitated once under X.A.N.A.'s control to destroy the Core of Lyoko. William doesn't use his levitating power when he is in a fight with the Lyoko Warriors, and the reason is unknown. In the silver suit, it requires his Zweihandler, and gives off a purple aura similar to William's Personal Super Sprint. In the Black Suit his sword helps aid in levitation but isn't required but without it he has a black aura similar to his Super Smoke.
In Code Lyoko DS, Levitation was Aelita's power; it was used as a replacement for Creativity and allowed her to cross chasms and gorges until her power gauge ran out.