Travel Air 4000
The Travel Air 4000 was a three-seat, open-cockpit biplane built by the Travel Air Manufacturing Company of Wichita, Kansas. It was the radial-engined member of the biplane family that began with the Model A, sharing the welded-steel-tube airframe of the OX-5-powered Model 2000 but fitted first with Wright Whirlwinds and later with a wide range of other air-cooled radials. Around 100 were built from 1927 under the 4000 name, in many lettered variants for sporting flying, mail carrying and training. Travel Airs worked as barnstormers and crop dusters across the United States, and the 4000 has had an unusually long afterlife: examples are held by museums across North America and a few still fly.