flight feather

US /ˈflaɪt ˌfeð.ər/
UK /ˈflaɪt ˌfeð.ər/
"flight feather" picture
1.

one of the large, stiff, and asymmetrical feathers on the wing or tail of a bird, essential for flight

:
The eagle soared high, its powerful wings propelled by strong flight feathers.
Scientists study the structure of flight feathers to understand avian aerodynamics.