Which part of the wing primarily assists during landing?

The correct answer is flaps because they significantly influence an aircraft's aerodynamic performance during landing. Flaps are movable surfaces located on the trailing edge of the wing that can be extended downward to increase the wing's surface area and curvature. This increase allows the wing to generate more lift at lower speeds, which is essential during the landing phase when the aircraft is operating at reduced speed.

By extending the flaps, the aircraft can maintain lift even when flying slower, enabling a steeper descent and a lower landing speed. This helps the aircraft land safely and reduces the distance required for landing, providing better control during this critical phase of flight.

Understanding the other components provides context: winglets help improve fuel efficiency and enhance stability in cruise but have minimal direct effect on landing. Ailerons are essential for roll control and maintaining the aircraft's lateral balance but do not directly contribute to lift during landing. The nacelle primarily houses the engines and does not play a role in lift generation during landing.