Boeing Co.'s future probably holds one and possibly two larger widebody jets and a supersonic transport, company executives say. But not the 7J7. When first proposed three years ago, the 7J7 _ ``J'' for the consortium of Japanese manufacturers interested in the plane _ was to be one of the most innovative planes Boeing ever built. It was to make extensive use of composites and other high-tech materials, ``fly by wire'' electronic controls, computerized instruments and a new ``unducted fan'' engine that would have external propellers. Trouble was, Boeing said after postponing the program last year, ``market indicators continued to present different requirements on airplane size and configuration.'' Translation: Nobody wants to buy one. Asked recently whether the 7J7 would ever be built, Philip Condit, executive vice president for production and engineering at Boeing Commercial Airplanes, said: ``As described at that point, probably not.'' He said manufacturers have to try to guess market demands 10 years into the future. ``Our best guess is there is going to be a fair amount of pressure, due to (airport) gate constraints, congestions, on the bigger sizes,'' Condit said. ``That's why the effort now on 767-X.'' The 767-X is a new, larger version of the 767 widebody, which comes in two sizes _ the model 200, which holds 216 passengers in two classes, and the 300, which carries 261. Condit said Boeing is considering a version that would seat 300 people and possibly a version for 350 passengers. The 767 is becoming more attractive to airlines thanks to a Federal Aviation Administration rule change earlier this year allowing the two-engine planes to fly routes 120 minutes away from usable airports. That qualifies it for use on many over-water routes. Richard Albrecht, executive vice president for sales and marketing at Boeing Commercial Airplanes, said the company expects the FAA to extend the authorization to 180 minutes soon, which would allow 767s to fly trans-Atlantic routes. Boeing also has plans for a supersonic airliner, but executives doubt it will fly in the next 20 years. ``The economics of the supersonic transport have to be roughly comparable to that of the subsonic transport in order for it to make sense commercially,'' Albrecht said. A supersonic flight between Los Angeles and Australia might take five hours instead of 15 aboard a 747, but Albrecht says he doubts too many passengers would pay double the fare to save that time. While the Concorde supersonic airliner has been successfully marketed as a premium trans-Atlantic service, ``I don't believe anybody will build the next generation of the supersonic transport to serve a niche market, which is what the Concorde is serving now,'' he said.