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.
Wingtip vortices make up the primary and most dangerous component of wake turbulence. Wake turbulence is especially hazardous during the landing and take off phases of flight, for three reasons. The first is that during take-off and landing, aircraft operate at low speeds and high angle of attack.