What is the primary mechanism behind lift production in airplane wings?

The primary mechanism behind lift production in airplane wings is the pressure difference created by wing shape. As an aircraft wing (or airfoil) moves through the air, its specific design (camber and angle of attack) causes the air pressure on top of the wing to be lower than the air pressure underneath. This difference in pressure results in an upward force known as lift.

Specifically, the air moving over the curved upper surface of the wing travels faster than the air underneath, which adheres more closely to the flatter bottom surface. According to Bernoulli's principle, this faster-moving air leads to a decrease in pressure above the wing while the slower air below maintains relatively higher pressure. This pressure differential is what generates lift, allowing the aircraft to rise off the ground.

The other options describe aspects of airflow and pressure but do not correctly identify the primary mechanism for lift. Lift is not produced by negative air pressure below the wing's surface or solely by increased speed of air above the wing but rather by the overall pressure difference due to the wing shape and angle.