Aeroplanes fly because they want to. Helicopters, becuase they have to ;~))
(Sorry Whirly!)
Seriously - forget that cr*p about curved upper surfaces they serve out in O Level physics. A wing generates lift because it displaces air DOWN. The equal and opposite reaction is that it goes UP. Stick your (simetrical) hand out of the window of a moving car (you never did this as a kid? And you are a Pilot???). Tilt it (give it some A of A), and it goes up. Just like the Extra. Give it negative A of A, and it goes down. Simple.
SSD