ELI5: How do airplanes stay in the air?

Imagine you're sticking your hand out of a car window while driving.

• If you hold your hand flat, it mostly just feels the wind.
• Now, tilt your hand up a little. Your hand gets pushed upwards, right?

Think of it like this:

• The air has to travel faster over the curved top of the wing.
• Because the air is moving faster on top, the air pressure on top gets lower.
• The air moving slower underneath has higher pressure.
• This difference in pressure—higher pressure pushing up and lower pressure pulling up—creates lift.

The airplane's engines help it go fast enough to create enough lift to overcome gravity, which is trying to pull it down. So, it's a balance:

1. Engines make the airplane go fast.
2. Wings use that speed to create lift.
3. Lift pushes the airplane up, fighting against gravity.
4. If the lift is strong enough, the airplane stays in the air!