Which type of flap system is known for increasing both wing area and changing wing camber?

The correct choice is Fowler flaps, which are specifically designed to increase both the wing area and change the wing camber during flight. The operation of Fowler flaps involves a mechanism that allows them to slide back and down, thereby extending the wing's effective area and altering the shape of the wing's airfoil. This combination of features significantly enhances lift at lower speeds, which is particularly beneficial during takeoff and landing phases.

While other flap types, such as split flaps and slotted flaps, also enhance lift, their design does not offer the same dual benefit of increasing wing area and camber simultaneously. Split flaps primarily increase lift by changing camber but do not contribute to a significant increase in wing area. Slotted flaps provide a mechanism to improve airflow and stall characteristics but don't enlarge the wing area to the extent that Fowler flaps do. Plain flaps are a more basic flap type that strictly alters camber without any additional area increase. Thus, Fowler flaps are unique in their capacity to effectively enhance both aspects, making them vital in certain aeronautical applications.