Fletching is the process of attaching feathers to arrow shafts.
Fletching creates drag on the end of the arrow, which causes it to fly straight.
Also, using different fletching to stabilize a projectile in flight (in this case an arrow), launched by a bundle-bow made of willow staves and pine needles. In the image there are three arrows with different types fletching:
Top - Tri-fletched for archery
Middle - White Pine Fletched for an atl-atl
Bottom - Bi-fletched for an atl-atl