a gun dog used to hunt or
A dog that tracks birds by scent in the air (not on the ground).
and Bird dog fee A "bird dog" refers business to a dealership or salesperson, and "bird dog fee" is the money he or she receives for doing so.
An Air Force light aircraft that flew over the battlefield
forward air controller, usually in a small, maneuverable single-engined prop airplane
A sporting dog bred and trained to hunt game birds.