Which of the following surfaces decreases lift by disrupting airflow?

Spoilers are aerodynamic devices that are specifically designed to disrupt the smooth airflow over an aircraft's wings, thereby reducing lift. When deployed, spoilers introduce turbulence to the flow of air, which decreases lift and increases drag. This effect is particularly useful during landing, as it helps the aircraft to descend more quickly by reducing lift, allowing for a steeper glide path and better control during descent and landing.

In contrast, elevators, flaps, and slats serve to increase lift and improve the aircraft's performance in various phases of flight. Elevators control pitch and help maintain stable flight paths. Flaps extend and increase surface area during takeoff and landing to enhance lift at lower speeds. Slats also improve lift by channeling airflow over the wing’s leading edge, preventing stall. Each of these surfaces is designed to enhance aerodynamics, whereas spoilers are unique in their primary function of reducing lift.