Photograph of a swept antenna on the underside of a Fairchild 24 aircraft, circa 1939. A person, mostly out of frame, points to the antenna from the image's left side.Inscription: "First swept antenna on Fairchild 24. 1939."
Photograph of a Learadio Beech 17R Staggerwing aircraft, circa 1930s-1940s.Stamped on verso: "Please credit Hans Groenhoff, [crossed out telephone number and address in New York City, New York]."Note attached to verso: "[letterhead: Norman Warren] /…
Photograph of a Learadio Beech 17R Staggerwing aircraft, circa 1930s-1940s.Stamped on verso: "Please credit Hans Groenhoff, [crossed out telephone number and address in New York City, New York]."