Harold F. Pitcairn, of Pittsburgh Plate Glass, was air enthusiast from 1915. In 1925 he hired brilliant Agnew Larsen to design for awakening civil market. Resulting Fleetwing biplane (7 November 1925) had 3 open cockpits in line. Formed Pitcairn Aircraft Inc. at Philadelphia, with plant at Bryn Athyn, PA. Sesquiwing, Arrow racer, Orowing and Fleetwing 2 led to classic PA-5 Mailwing (August 1927) cargo carrier of which 20 were made in several versions. PA-6 Super Mailwing of 1928 again led to about 25 of several versions, ending with 300-hp PA-8S before Depression closed fixed-wing business, see Pitcairn Autogiro Co.