Flaps are movable surfaces on an aircraft's wings that help control lift and drag during flight. They can be extended or retracted to change the wing's shape, allowing the aircraft to fly at slower speeds, especially during takeoff and landing. By increasing the wing's surface area, flaps enhance lift, making it easier for the plane to become airborne or maintain stability at lower speeds. There are different types of flaps, including slotted flaps, fowler flaps, and plain flaps, each with unique designs and functions. Pilots use flaps to improve performance and safety, ensuring smoother landings and takeoffs in various conditions.