Due Pan Am had no domestic route system it was not allowed to operate a flight from its World Port in New York to Tokio via L.A. So it had to fly the route "non stop". The Boeing B747-121 was not able to do this, so Pan Am asked Boeing for an airliner with that ultimate range. Boeing went back to the drawing board and at the end there was the Boeing B747SP. SP means "special performance" and that was it. With a full payload and 233 passengers in an 3 class seat configuration it flew non stop, almost 7000 statute miles, from New York to Tokio. Pan Am opened the route on April 25th 1976. That was what Pan Am wanted, but the success of the B747SP was poor. Soon the newer versions of the 747's could fly the same distance, but with 350 passengers and more cargo capacity. Pan Am had 11 of the SP's. The B747SP's went out of service with the sold of the "Pacific Division" on April 22nd 1985. They were sold to United.