Definition
A small, near-vertical aerodynamic surface attached to the tip of an aircraft wing, designed to reduce induced drag by weakening the wingtip vortex that forms when high-pressure air beneath the wing spills around the tip into the lower-pressure air above it.
Plain English
A small upward-angled extension on the end of a wing that reduces the swirling air at the wingtip, which makes the aircraft more efficient and saves fuel.
Context Anchor
Seen during aircraft walkarounds, in aircraft performance discussions, and when identifying aircraft wing designs.
Derivation
From 'wing' plus the diminutive suffix '-let,' meaning 'small wing.' The name reflects what it is: a little wing standing on the end of the main wing.
Why Pilots Care
Reduces fuel burn and increases range or payload by lowering drag without adding significant weight.
Analogy
A winglet is a little like a fence at the edge of a wing. It helps keep the air from spilling around the tip as strongly, which reduces wasted energy.
Intuition Check
A winglet is not a separate little wing meant to fly the airplane by itself. It is a wingtip device that helps the main wing work more efficiently.
Example Sentence 1
The 737-800 with winglets burns less fuel on long legs than the same aircraft without them.
Example Sentence 2
After installing winglets, the aircraft showed a measurable reduction in fuel flow at altitude.