Why do airplanes have winglets?

Answer: To reduce drag and save fuel

To look more modern — Wrong. While winglets do look modern, they serve an important aerodynamic function: reducing induced drag from wingtip vortices. At wingtips, high-pressure air below the wing curls around to low-pressure air above, creating turbulent vortices that cause drag. Winglets disrupt this flow, reducing drag by 3-7% and saving significant fuel on long flights—worth millions annually.

To balance the wings — Wrong. Wings are balanced through overall design, not winglets. Winglets reduce induced drag by disrupting wingtip vortices (air curling from high pressure below to low pressure above the wing). This turbulence creates drag that wastes fuel. Winglets redirect this airflow more efficiently, reducing drag and fuel consumption by 3-7%. The fuel savings justify the added weight and cost.

To reduce drag and save fuel ✓ — Correct! At wingtips, high-pressure air below the wing curls around to low-pressure above, creating turbulent spiral vortices that cause induced drag (wasted energy). Winglets disrupt these vortices by redirecting airflow, reducing drag by 3-7%. This saves significant fuel—for airlines flying thousands of hours yearly, this means millions in fuel cost savings, easily justifying the winglet installation cost.