Army O-1 two seat, fixed wing aircraft used for aerial observation and spotting for artillery or fighter bombers. Bird dog units were called Recon Airplane Companies (RAC).

Referral fee.

a gun dog trained to locate or retrieve birds

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.