DOUGLAS last passenger aircraft, now called the Boeing 717, is about to reach its production end. First flown as the DC9 in 1965, then the McDonnell Douglas MD80/90, its home factory at Long Beach is scheduled to hand over the last of 2,439 planes sometime in May to Air Tran. With the Embraer 145 line also showing signs of fatigue it does seem that the era of the rear engine jet is coming to an end. Starting with the Sud Aviation Caravelle and including the BAC 1-11, these aircraft were quieter and faster than their under wing slung competitors and much more popular with passengers. Technically they were number two to the aircraft with the engines underslung the wings.