One of the physical impossibilities amusingly discussed was the scene in Superman: The Movie (1978) where Supes flies up to catch Lois Lane who is falling down the skyscraper. According to the physics, due to terminal velocity Lois would've been plummeting down at 120 miles/hr. In order for Superman to reach her while she is still high up, starting as he is from the ground, he has to fly farther and faster than Lois is falling - about 1000 times faster or 120,000 miles/hr. So Superman's "rescue" wouldn't be a pretty sight as he impacts Lois at that speed. (Which of course makes Neo's rescue of Trinity in Matrix Reloaded look even more insane, but since it isn't "real"...)
Superman's very ability to fly could perhaps be due to his usage of the Earth's magnetic field. Or, more far-fetched (though still scientifically plausible, according to the experts) is the idea that Supes is actually manipulating gravitons with his super-advanced physiology, riding on "gravity waves." In effect, anti-gravity. Cool!
Sorry, don't mean to bore you all. It's an entertaining hour of TV if you're a Superman fan.
