How do ailerons primarily affect an aircraft?

Ailerons primarily affect an aircraft by controlling roll. They are hinged flight control surfaces located on the outer portion of each wing. When the pilot moves the control yoke or stick to the left or right, one aileron deflects upward while the other deflects downward. This differential movement alters the lift generated by each wing; the wing with the aileron deflected downward generates more lift, causing that side to rise, while the opposite wing, with the aileron deflected upward, decreases lift and drops. This difference in lift results in the aircraft rolling around its longitudinal axis, which is essential for maneuvers such as turning and maintaining balanced flight. Understanding the role of ailerons in controlling roll is crucial for pilots, as it directly impacts the aircraft's orientation and control in various flight situations.