What are wingtip vortices and how do they affect aircraft performance?

Wingtip vortices are rotating air masses that form at the wingtips due to pressure equalization between the high-pressure lower surface and low-pressure upper surface. They create downwash behind the wing, which tilts the lift vector backward creating induced drag. Wingtip vortices also pose a hazard to trailing aircraft (wake turbulence). Winglets, raked tips, and high aspect ratio wings reduce vortex strength and induced drag.