The 707's design came from the Boeing 367-80, which was a prototype jet. The very first 707, the 707-120, had Pratt & Whitney JT3C turbojet engines. Pan American World Airways started using the 707 on October 26, 1958. Other types of 707 are the 707-138 and the 707-320. Both of these started being used in 1959. A smaller version, the Boeing 720, was made in 1960. The 707-420 had Rolls-Royce Conway 508 turbofan engines. It was made in 1960.