Wedged between Tim Burton's unrealized vision for Superman Lives and Bryan Singer's much-criticized Superman Returns in the storied on-screen history of the Man of Steel is Superman: Flyby, a planned origin story that turned out to be another false start for the superhero franchise.

With a script by J.J. Abrams in hand, director McG eyed Scarlett Johansson as Lois Lane and Shia LaBeouf as Jimmy Olsen. For the lead role, he screen-tested several relatively unknown actors, including the current Man of Steel Henry Cavill. But who did he want to play Superman's arch-nemesis ?

While making the rounds for his new action/romantic comedy This Means War, McG revealed to The Playlist that he'd secured Robert Downey Jr. ahead of the actor's Hollywood comeback. "We had Robert Downey Jr. locked up to be Lex Luthor, which I think would have been extraordinary," he said.

Ultimately, though, Flyby fell apart, primarily because McG's fear of flying prevented him from going to Sydney, Australia, where Warner Bros. wanted to shoot the bulk of the film.

"J.J. wrote the script, and we got that to a really good place in the end," he said. "But I’m to blame for [the film not happening]."