The trailing edge of the wing is the part that is referred to as the flaps.
The flaps are simply called flaps.
winglett
Flaps generally change the geometry of the wing for landing and take off speeds
winglett
the wing flaps go up and down
The wing is the main flying surface. Control surfaces include the ailerons, flaps and slats.
To reduce the drag
Flaps in some cases are used to increase wing surface area. In most small single and multi-engine airplanes the flaps that are being utilitized usually plain, split or slotted, do not increase the surface area. They increase the camber (camber being the distance between the mean thickness of the wing and the line going from the leading edge to the trailing edge (called the chordline)), and also increase the coefficient of lift (or how hard the wing is working to produce lift). On most transport category airplanes they utilize what is called fowler flaps. These flaps increase the surface area of the wing by moving the flaps rearward on a track. This rearward movement increases those things stated earlier and also increased the surface area, which also produces more lift.
Airplanes use a combination of slats and flaps in order to increase lift and increase drag. The slats are located on the leading edge of the wing and the flaps on the trailing edge. Flaps and slats when extended forward and aft increase the wing area which increases lift. When the flaps and slats are further extended they curve downwards increasing the camber of the wing which also increases lift. The greater the lift, the greater the drag. Deploy the flaps a little and lift overcomes the drag, fully extend them and the drag overcomes the lift. For takeoff the flaps and slats may be extended just a few degrees to increase lift. When flaps and slats are fully deployed in landing configuration, the lift is great but so is the drag and this in turn helps to slow down the airplane on decent to land.
lift decrease and increase drag
No. On MOST airplanes, ailerons are separate from flaps. Ailerons are used to help steer the airplane, while flaps are lowered to change the aerodynamic shape of the wing to provide more lift during take off and landing.