8The plane crash didn’t really kill him
Steve Trevor is expected to “come back to life,” but that’s contingent on the idea that he actually died in Wonder Woman. We didn’t see him die. We just saw him fly off with some poison and blow himself up to save the world.
As we’ve seen from other comic book
movies, if we don’t actually see them perish (and even then, that’s no guarantee), then they’re probably still alive. Red Skull got sucked into a beam of light in the sky, but we didn’t see him actually die, so he showed up on Vormir seven years later. Maybe the blast didn’t kill Steve – it might have sent him forward in time or imbued him with immortality.