Definition
The straight-line distance from one wingtip to the other, measured perpendicular to the airplane's centerline.
Plain English
How wide the airplane is from wingtip to wingtip.
Context Anchor
Seen in aircraft specifications, ground handling, hangar spacing, and ground effect discussions during takeoff and landing.
Derivation
From 'wing' plus 'span,' an old English word meaning the distance between two points. The same idea appears in 'span of a bridge.' It simply names the distance the wing reaches across.
Why Pilots Care
Affects decisions about taxiway and hangar clearance, wingtip separation from obstacles, and the amount of induced-drag reduction experienced in ground effect.
Intuition Check
Wingspan is not the length of one wing and not the total wing area. It is the airplane’s full side-to-side width from wingtip to wingtip.
Example Sentence 1
Ground effect is typically noticeable when the airplane is within one wingspan of the runway surface.
Example Sentence 2
A larger wingspan increases the airplane's benefit from ground effect during the initial climb after takeoff.