[Pilot starting up "Baby," a prototype North American P-51 Mustang]

Photograph of a pilot starting up "Baby," a prototype North American P-51 Mustang aircraft, Inglewood, California, circa 1940s.

Inscription: "Warm 'er up."

Item from the Margery Watson World War II Photographs album pages, circa 1940s. Album pages contain photographs and small ephemera related to Watson's work for North American Aviation during World War II.