I think the best explanation for all of Superman's powers is explained by The Unified Theory of Superman's Powers. http://www.qwantz.com/fanart/superman.pdfThe Unified Theory of Superman's Powers. It basically says that all of powers Superman has are possible if His power is the ability to manipulate, from atomic to kilometer length scales, the inertia of His own and any matter with which He is in contact.
But as far as applying real world physics there is also a great article that describes it on i09 called the Physics of SupermanThe physics of Superman. Here is the excerpt:
Negative mass and positive mass are supposed to fall towards each other, so he feels gravity the same way everyone else does. However, he also feels air molecules all over his body. If he turned them to negative mass, they would push his body upwards. By contrast, if he turned the outer skin of his body to negative mass (or his aura), the air pressing back against it would cause it to push him forward. So Superman uses air pressure and negative mass to fly around planets with atmosphere.
I of course have a whole other theory but their is nothing canon specific that supports mine so I won't post it. I really do think these two articles answer most Superman power questions.