While in the air, it is possible to move your body in ways that gives the impression of hang time, or air walk. The center of gravity describes a parabolla, but the head might not (if hands and feet don't). An example is bringing the ball from above your head to stomach level while in mid air. Another is straightening your forward leg from a forward postion to an underneath position. As far as the upper body is concerned, there is a second "jump" while in the air in both cases. MJ mastered both, in addition to having pure jumping power. When I personnally try to be like Mike, I can do it just sufficiently to feel the hang effect.
Although I've never done it, it would be interesting to chart the trajectory of a red dot on MJ's waist and one on his head from video. The waist should form a nice parabolla, the head a distorted one (hands and feet even more so).