The wing directs the flow of air downwards. The flow doesn't separate except at high angles of attack (stalling). You can go into arbitrary levels of detail (wh

The wing directs the flow of air downwards. The flow doesn't separate except at high angles of attack (stalling). You can go into arbitrary levels of detail (why doesn't the flow separate?, how thick is the affected layer?, etc.) but it doesn't change the fact that mostly we know the answers to all those questions.