Winglets are small, vertical extensions at the tips of an aircraft's wings. They help reduce drag, which is the resistance an airplane faces while flying. By minimizing this drag, winglets improve fuel efficiency and enhance the overall performance of the aircraft. These aerodynamic devices work by altering the airflow around the wings, reducing the formation of vortices that can create turbulence. Many modern commercial airplanes, such as those made by Boeing and Airbus, are designed with winglets to optimize their flight capabilities and reduce environmental impact.