Flight - Part 2

Superman's first screen appearance was the cartoon series by Max Fleischer. This was early enough that Superman didn't quite fly. He made tall leaps (and single bounds).

A Superman serial from the 1950s was shot in live action but when Superman flew the actor was replaced with an animated figure who zipped back and forth. I think that this was to maximize screen time for the flight which was never more than a second or two, anyway.

Hanna-Barberra did a long-running version of Superman but used limited animation. Most of the flying was with a fixed cell of Superman while the background moved.

When Chris Reeve took over the roll, he just floated up (up and away). The more recent Superman and Justice League cartoons did the same as did Superman Returns.

When John Byrne remade Superman in the 1980s, he said that he thought of many of Superman's power as some form of psychic power. He didn't actually use X-rays to see through objects, he used ESP. He didn't melt things with heat from his eyes, he used telepyronics. While he was tough, much of Superman's invulnerability came from a personal force field (which covered his suit but not his cape). By this reasoning he doesn't exactly fly, he levitates himself.

This would explain how Superman can carry things that should break apart. In the first movie Superman takes Lois flying. She appears to fly at arm's length. This is consistent with Superman flying psychically. If he was propelling himself by any normal means then Lois would have been trailing behind due to air friction. If he levitates himself and what ever he touches then Lois could easily fly at arm's length.