Its complex...The example normally given is, the wing is shaped a little flat in the under side and curved on the top. So that would explain the flow as you mentioned. However when an airplane flies upside down, its not sucked into the ground ;-)
It seems nobody really knows:
"No One Can Explain Why Planes Stay in the Air"
https://www.scientificamerican.com/article/no-one-can-explai...
Edit: Added brief from article above:
------------------------------------------------------------
- On a strictly mathematical level, engineers know how to design planes that will stay aloft. But equations don't explain why aerodynamic lift occurs.
- There are two competing theories that illuminate the forces and factors of lift. Both are incomplete explanations.
- Aerodynamicists have recently tried to close the gaps in understanding. Still, no consensus exists.
------------------------------------------------------------
It seems nobody really knows:
"No One Can Explain Why Planes Stay in the Air"
https://www.scientificamerican.com/article/no-one-can-explai...
Edit: Added brief from article above:
------------------------------------------------------------
- On a strictly mathematical level, engineers know how to design planes that will stay aloft. But equations don't explain why aerodynamic lift occurs.
- There are two competing theories that illuminate the forces and factors of lift. Both are incomplete explanations.
- Aerodynamicists have recently tried to close the gaps in understanding. Still, no consensus exists.
------------------------------------------------------------