How can airplanes defy the laws of gravity?
Aircraft do not defy the law of gravity, they produce a sufficient force to overcome gravity, just as you do if you decide to jump in the air. There are four main forces acting on an aircraft, thrust from the engines, drag on the airframe, gravity pulling down and lift generated by the wings. Lift is generated in two ways, one being the Bernoulli effect. This is why aircraft have curved wing surfaces – the air has to flow faster over the top surface and fast flowing air has low pressure (try holding two pieces of paper up vertically and blowing between them). The higher pressure beneath the wing causes lift. The second way lift is generated is by the angle of attack of the wing’s lower surface, air hitting this can be deflected downwards and also generate lift. Once the size of the lift is greater than the weight of the plane then gravity will be overcome and the plane will rise. Once cruising altitude is achieved the lift force is balanced with the weight and the aircraft stays at a c
