There is two theorys on flight. Bernoullie, and Newtononian. Newton says it's from the air particles hitting the bottom side of the wing. Bernoullie says it is from a difference in pressures. The air traveling over the top of the wing has farther to travel so it is moving faster creating an area of lower pressure. The pressure difference is what creates the lift. The reality is that they don't fully understand how the lift is produced, only how to manipulate it. I only have limitied exposer to lift from the handfull of aviation classes I took when I was going to school for ATC.