The Boeing 2707 was a failure. How can you say it was a success? The idea was to build a large supersonic transport, and nothing was built except a wooden model. yeah they had lots of research, but the government thought that there would be demand for 500 SST's by 1990, and there were never more than 36 SST's ever built, and there was never a new SST design past the year 1971. As cool as an SST is, the imaginations of people from the 1950's and 1960's, that SST's would rule the world, won't come true. Plus, teh Boeing 2707 was designed to hold 250 people, to be a useful plane, rather than a cramped RJ-sized jet of the Concorde or Tu-144. Yeah, the Concorde cost less, but the 2707 was to be faster, land slower, carry more people, fly farther, and be an all-around better and more useful airplane; it proved to cost too much, and the 767 that came 12 years later held the same amount of people, was as fast as the 707's, it was more comfortable, and took over to become the most used transatlantic airliner. The Concorde and 2707 were incomprable airplanes, aside from the label SST.

A Boeing 747-100 and a Concorde used almost the same amount of fuel, and the 747 could carry three times as many passengers over a New York to London route. I'm sorry if you think otherwise, but you're thinking like there's demand for another SST, there really isn't. Maybe the SSBJ's will be somewhat popular, but as the Sonic Cruiser proved, airlines want profitability, seating capacity, and effeciency over speed. A 747 is pretty fast anyways.