This series documents the commercial use of Fowler's designs, specifically the Fowler flap. Included are photographs that illustrate the use of the flap on various airplanes in different modes of extension. Items of note include a negative of the first working model of a Fowler variable area wing constructed in 1920, photographs of the first experimental airplane using a Fowler flap, the Canuch and other early experimental planes. This series also includes a limited number of press releases, correspondence, and technical reports of tests on Fowler flaps.