Airlines did not really want a 300+ seat Airbus A300, so Airbus Industrie made the A250 proposal. This later became the A300B, which had 250 seats and did not need a new engine design. This made the plane much cheaper to design, as the Rolls-Royce RB207 which would have been used in the A300 made up a lot of the costs. The RB207 had also had design problems and delays, since Rolls-Royce was concentrating on designing a different jet engine, the RB211, for the Lockheed L-1011 The A300B was smaller but lighter than its American rivals.