While I was in aviation, we called it "lift" that allowed an airfoil to overcome gravity. LIft as happens on the top of the wing surface.

There is a fair amount of downward movement of some airfoils while they are generating their maximum lift, like in slow flight, or take off, or landing, or hover. 

The bottom sides of most aircraft wings are "dirty" compared to the top side. There's a reason for that. Even in inverted flight like aerobatic planes can perform, they don't fly as efficiently with the dirty side up. There's a reason for that. Yes, airplane wings, fuselages, & their propulsion system do disrupt the air and make things spiral all over the place. But that usually ceases with a height approximately equal to the wingspan of the aircraft. It dissipates eventually.

If you've got a lot of spare time, you can google "how airplanes fly". There's probably 3,000,000 articles written on it.

Now, there is something called vortex generators, or commonly called winglets that interrupt the normal airflow process. Again, lots of info out there to read.

As I mentioned in another post, I'm also considering inventing an airfoil that would mount to the boom of a sprayer. Even at 10 mph, you can generate lift. I assume most posters on AT over the age of 60 probably flew kites when they were kids. I'm not even sure they make or sell kites any longer. Every spring it was a rush to the hardware store to find the newest kite creation. So, anyway, if it's the wing that helps push the 2 gpa into the canopy, I might be able to harness some of that "push".