Skin discoloration can be due to changes in melanin. Melanin is a skin pigment that gives color to the skin. Changes in melanin can also cause skin to be patchy. Treatment for skin discoloration includes using topical treatments.
Winglets increase an aircraft's operating efficiency by reducing what is called induced drag at the tips of the wings. An aircraft's wing is shaped to generate negative pressure on the upper surface and positive pressure on the lower surface as the aircraft moves forward.
An airplane is a heavier-than-air flying machine whose primary purposes are transport and research. A plane's wings, engines, and control surfaces enable it to fly. Control surfaces are movable sections of the wings and tail. The power of the engine(s) is responsible for pushing the plane through the air.