Because in another life (um… movie), he was a pilot.
(Pic: Adrian Pasdar as “Chipper”, sitting behind Anthony Edwards)
Come on! If this joke hasn’t already proliferated, it should!
(Truth is, from episode 1 I’ve already recognized “Nathan Petrelli” - Adrian Pasdar – as one of the bit role actors in the 1986 blockbuster Top Gun, the film that made Tom Cruise famous. But coining jokes from superficial stuff like this could be dangerous to someone’s health, which is why it took me this long to deliver the punch. Now I gotta get outta here before I’m the one who gets punched  )