How Planes Fly

Ever wonder what keeps them up there? How do they do it? Here's how it's done:
An aircraft in flight is acted upon by four forces: lift, gravity, thrust and drag. Each of these oppose each other, and balance each other out like this:

Lift = Gravity

Thrust = Drag

What are they and what do they do?

Thrust: It's the force that moves an airplane forward through the air. It's made by a propeller or a jet engine.

Drag: This is the air resistance that tends to slow the forward movement of the airplane.

Gravity: It's the force that pulls all objects towards the earth.

Lift: This is the upward force that is created by the movement of air above and below a wing. Air flows faster above the wing and slower below the wing, creating a difference in pressure on the wing, pushing up, and keeping it flying.