The epitomy of commerical jet airliner travel, the Boeing 707 served with all the principal carriers bringing new standards of comfort, speed and efficiency to airline passengers. Pan Am was the first major airline to order it and flew its fleet emblazoned with the famous 'Clipper' names. BOAC placed a substantial order and insisted on Rolls-Royce Conway engines rather than the Pratt & Whitney JT series engines favored by American customers. Very few 707s are now flying passengers and many military versions fly as AWACs, tankers or transports..