If you're old enough to remember the first Superman film, you'll recall the tagline for the movie: "You'll believe a man can fly." Richard Donner's first hurdle in pre-production was making the flying look believable. If the audience didn't believe Superman was flying, the rest of the film would have been in vain.
Warner Bros. has a new clip for their upcoming movie, Green Lantern, and while the effects look very poor, the flying scene is even worse and totally unbelievable. I realize it's just another summer blockbuster and Warner Bros. doesn't have a good track record with their DC Comics' characters but it still makes me wish all directors had the standards of Richard Donner.