How a plane can fly

There are four main forces that act on an airplane to keep it in flight: lift, weight, thrust, and drag.

Lift is the upward force that is generated when air flows over the wings of an airplane. The curved shape of the wings and their angle of attack create a difference in air pressure between the upper and lower surfaces of the wings, which results in lift.

Weight is the downward force that is exerted on the airplane due to gravity. The weight of the airplane must be balanced by the lift generated by the wings in order for the airplane to stay in the air.

Thrust is the forward force that is generated by the airplane's engines. This force is used to overcome drag, which is the backward force that is exerted on the airplane due to air resistance.

In order for an airplane to take off, it must first generate enough thrust to overcome drag and accelerate down the runway. Once it reaches a certain speed, the wings generate enough lift to lift the airplane off the ground.

During flight, the pilot adjusts the angle of attack of the wings and the amount of thrust being generated by the engines to maintain altitude and speed. To descend, the pilot reduces the amount of thrust and lowers the nose of the airplane, which increases drag and reduces lift.