Question: how do planes fly

Ceri-Wyn Thomas answered on 24 Jun 2010:

Planes fly because the force of lift generated by their wings exceeds the weight of the plane. Because the force up is larger than the force down, the plane is lifted up. The reason wings generate lift is because of their shape. When the wing moves through the air, more air goes underneath the wing the over the top of it. This means that there is a higher pressure underneath the wing, and a lower pressure on top, so the wing is forced up.

You can try this next time you are driving in your car – stick your hand flat out of the window when you are moving fast, and tilt it so that the front part of your hand is higher up than the back part. You should feel the force of lift pushing your hand up – this is exactly the same as for the plane. You’ll feel that the faster you go, the stronger the force – this is the same for the plane, it has to go a certain speed to have enough force to lift it up. If the engines fail and it can’t go forward fast enough, it will crash.

Some people claim that we don’t really know how flight works. This is a false rumour, although certainly in the past a number of very smart people didn’t know the answer to this question.