In aeronautics, flaps and slats are used to control what on an aircraft?

The story behind the answer

Flaps (on the wing’s trailing edge) and slats (on the leading edge) change the wing’s shape and camber to increase the coefficient of lift, especially at low speeds. Slats open a slot that energizes airflow over the wing, delaying stall, while flaps increase curvature and sometimes area. Pilots deploy them mainly for takeoff and landing so the aircraft can fly safely at slower speeds.

They do add drag as a side effect, but their primary purpose is lift augmentation—thrust comes from engines and weight is gravity. Memory tip: “SLats = leading-edge Slot; FLaps = back to ‘FLoat’ at low speed.”