 Magnetos line "When will these people learn how to fly?" is a  reference to the fact that some of the characters (Jean Grey and  also Rogue, who gets the ability from permanently absorbing Ms.  Marvels powers in the comics) have the ability to fly in the comics  but havent yet in the films. The only characters with the power of  flight in the comics that have shown this ability in the movies are  Magneto and Storm.