Video narration
How does a heavy airplane avoid dropping out of the sky? Think of a paper airplane. Moving through air, it can stay up, but a real airplane needs more than a fold. Its wings need moving air, and engines keep it going. But here's the key: the engines don't directly hold the airplane up. Moving wings push air down, and the air pushes back up. That upward force is called lift. Wing shape and pressure differences help create it too. Now, two pairs of forces: lift upward against weight, the pull downward; and thrust forward against drag, which resists motion. When lift balances weight and thrust balances drag, the plane can hold a steady altitude. It needs enough speed through the air to keep producing lift. So why doesn't it fall? Moving wings push air down, creating lift that balances weight while engines keep it moving forward.