Video narration
How does something as heavy as an airplane avoid simply falling from the sky? Think about a paper airplane. Once you throw it, four forces work together: weight pulls down, lift pushes up, thrust moves forward, and drag pushes backward. Here's the key: the engine does not hold the airplane up. The wing does. As the paper airplane moves, its wing sends air downward, and the air pushes the wing upward. A real airplane uses the same idea, with shaped wings and engines keeping air flowing over them. The engine's job is thrust: forward motion. The wing's job is lift: an upward force created by moving through air. In level flight, lift balances weight, while thrust overcomes drag. So why doesn't the plane fall? Moving wings turn forward motion into enough lift to balance its weight. The engines keep it moving; the wings keep it up.