简单的说，飞机起飞主要是靠发动机的巨大拉力和推力，使飞机滑跑时产生很大的前进速度，然后使机翼产生足够的升力。飞机才能起飞。

Why can an airplane fly?
Generally speaking, the reason why the airplane can fly is that engines produce great pulling and pushing forces which make the airplane taxi in high speed and give enough force to the wings so the airplane can fly.