Winglets are vertical extensions of wingtips that improve an aircraft's fuel efficiency and cruising range. Designed as small airfoils, winglets reduce the aerodynamic drag associated with vortices that develop at the wingtips as the airplane moves through the air.

Why do winglets reduce drag?

By significantly reducing the size of the wingtip vortex, winglets reduce induced drag—the aerodynamic drag created by an airfoil when it is producing lift. ... This airflow forms a vortex that causes induced drag, reducing the wing's aerodynamic efficiency.

Do winglets actually work?

Winglets are actually little wings that generate lift. And, just like any other wing, they generate lift perpendicular to the relative wind. ... It might not look like much, but that little bit of forward lift helps - it opposes the drag produced by the vortices when they're strong.