Besides the supersonic Concord and Tu-144, the Convair 990 was the fastest commercial airliner ever produced. The design featured unique anti-shock bodies on the upper wings to reduce drag at high speed. The 990 used a civilian version of the GE J79 engine with a fan stage mounted at the rear of the engine. The high performance meant the airplane used a lot of fuel. With a smaller passenger capacity than its Boeing and Douglass competition, the airplane was not a sales success. Only 37 aircraft were sold.