Yeah I couldnt believe that when I read it about his cameo. This is what Richard Branson said about his Superman Returns cameo "Brian [Singer] invited me to appear in the Superman film and he's using a Virgin Galactic airship in the film," Branson said. "I think today I'm going to be doing a fun little cameo role with my son Sam so it's going to be a good day."
It's believed Branson was dressed up as an astronaut for the scene, in which Lex Luthor tries to shoot down Branson’s Virgin Galactic craft!