How do planes fly?
Imagine this: Stick your hand out of the window of a car that travels at around 60 mph, and you will notice how lift is being produced as you twist your hand up and down. As the car accelerates, you will notice that no matter how you shape your hand, lift is always being produced.
However, the most efficient lift-producing shape is that similar to a wing.
The elevator (at the back of a plane) works with the wing to make the aircraft go up and down. The elevator changes the pitch of the aircraft, or nose up or nose down. As the elevator deflects upward, more air is hitting the top surface than the bottom, therefore creating a force downward that pitches up the aircraft.
So how do wings generate lift? The curved shape of the wing and the inclined angle mean that as the aircraft accelerates, more air is smashed into the bottom than the top, therefore creating a higher pressure at the bottom and a lower pressure at the top. Therefore, the pressure difference creates a force upward, and if the force is greater than the gravity of the aircraft, then the planes will take off.