flight feather

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Any of the comparatively large, stiff feathers of a bird's wing or tail that are necessary for flight.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun ornithology Any asymmetrical feather of the wing or tail of a bird.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun any of the larger wing or tail feathers of a bird