freight dog
n.— «Prince said Gross had been a flight instructor and a “freight dog” for the company for four years. A freight dog is a term for a pilot who flies cargo.» —“Pilot in plane crash identified” Pantagraph (Bloomington, Illinois) Nov. 10, 2005. (source: Double-Tongued Dictionary)
Further reading
There are lots of names for mixed-breed dogs, such as Texas brown dog, TBD, Heinz 57, duke’s mixture, poi dog, and potcakes. Danes have a couple of creative names for them that involve traffic: A mutt may be called a gadekryds, or “street...
A listener named Mark now lives in San Diego, California, but grew up in Chicago, Illinois. There, he recalls, when he and his friends played sandlot baseball, cards, or board games, if an opponent tried to get around the rules and then got called...