Bernoulli's theorem helps us understand how it is possible for an airplane, an object heavier than air, to achieve lift. Bernoulli used the term "air pressure" to explain how airplanes fly. Bernoulli explained that slower-moving air produces high air pressure, while faster-moving air produces low air pressure.
The term air pressure refers to the amount of push or pressure exerted by air particles of an object. The reason why airplanes can produce lift is because of how their wings are shaped. The designs of these wings carefully follow Bernoulli's theorem.
Since faster-moving air equals the low air pressure, the top of the wings is designed to allow faster moving air over the wings, while the beneath of the wings is designed to allow slower moving air to produce high air pressure. That way, the high air pressure underneath is enough to cause the plane to fly.