The Boeing Company invested $16 million (two-thirds of the company's net profits from the post-war years) to build the Dash 80 prototype for a long-range jet aircraft. It was developed in secrecy and designated Model 367-80 to disguise it as an improved version of the C-97 Stratofreigther. It was subsequently nicknamed the "Dash 80," had jet engines and swept wings, and was very different from the straight-wing, propeller-powered Stratofreighter. Because the prototype was constructed to sell first as a military-tanker transport, it had few windows and no seats, but had two large cargo doors. A week after its first flight, the Air Force ordered 29 tanker versions, the KC-135.