In October 1926 National Air Transport (NAT) sent out a request for bids for a transport aircraft for mail and passengers to be powered by a single Wright Whirlwind engine. The new transport was to have at least 100cu ft of cargo space and be capable of carrying a 1,000lb (453kg) load at 105mph (170km/h). NAT also specified that a demonstrator had to be available for flight evaluation within two months. The Travel Air Co board decided to bid on the NAT programme even though the response time was fairly short. In 38 days, the team led by Walter Beech and Clyde Cessna designed, constructed and delivered the prototype Travel Air Model 5000 to NAT for evaluation.
The Model 5000 broke with the biplane tradition. It was a high-wing monoplane with a 51ft 7in (15.72m) wing span. The single Wright J-5-C Whirlwind radial engine provided 230hp and its mounting had been designed to allow an engine change within 20 minutes. The pilot sat well above the passenger cabin in a heated cockpit under a fully enclosed jettisonable canopy. Travel Air designed the cabin to make the passengers as comfortable as possible. The heated cabin was soundproofed and had large windows for good visibility. Some of the other advanced features of the Model 5000 were a self-starter, wheel brakes and retractable landing lights.
Walter Beech delivered the first aircraft to Kansas City on 18 December 1926 and, after evaluating the prototype, NAT bought eight Model 5000s to be delivered within 120 days, to bolster service on its Chicago to Dallas route (including a stop at Wichita). The first NAT aircraft was ready on schedule and was first flown by Beech with several passengers on board among which were E P Lott of NAT, Marcellus Murdock and Jack Turner. It was delivered on 28 April 1926 and the second aircraft was ready in May but NAT did not need it so soon and released it for sale. This aeroplane was eventually bought by Pacific Air Transport, in California.
NAT’s 5000s were first used to carry only mail but began carrying passengers in the autumn of 1927 by special arrangements. By early 1928, they were carrying passengers regularly between Chicago and Kansas City at $62.50 one way. Only one Model 5000 was lost while in service. On 20 January 1929, aircraft c/n 177A piloted by John B Story, crashed at Davenport, Iowa.