What are ailerons primarily used for during flight?

Ailerons are primarily used for steering the aircraft by affecting lift. Located on the trailing edges of the wings, ailerons control the roll of the aircraft around its longitudinal axis. When a pilot raises one aileron while lowering the opposite one, it changes the flow of air over each wing. The wing with the raised aileron experiences a decrease in lift, while the wing with the lowered aileron sees an increase in lift. This differential lift causes the aircraft to roll towards the wing with the lower lift, effectively steering the aircraft in the desired direction.

The other options do not accurately represent the primary function of ailerons. Increasing drag on the wings, while related to controlling aircraft performance, is not the main purpose of ailerons. Similarly, controlling the pitch of the aircraft is primarily managed by the elevator, not the ailerons. Stabilizing the aircraft during descent involves factors like trim and elevator use, rather than ailerons. Therefore, the correct choice reflects the essential role ailerons play in controlling the aircraft’s roll and steering capabilities during flight.