What design feature primarily enables an aircraft wing to produce lift?

The design feature that primarily enables an aircraft wing to produce lift is the difference in air pressure created above and below the wing. When a wing is designed with an airfoil shape, the airflow over the top surface of the wing travels faster than the airflow under the bottom surface. According to Bernoulli's principle, the increase in the speed of the air results in a decrease in air pressure above the wing.

This difference in pressure leads to higher air pressure beneath the wing, which pushes the wing upward. The lift generated in this manner is essential for the aircraft to rise off the ground and maintain flight. Recognizing that lift is fundamentally tied to the pressure differential—higher pressure below and lower pressure above—helps clarify why design aspect is critical for effective wing performance.

Therefore, the correct answer reflects the essential aerodynamic principle that allows wings to generate the necessary lift for flight.