My point was simply that the US abandoned development of their own SST when they found out that the sonic bangs would be unacceptable. That, and the eye-watering cost, killed the SST project. In 1964 they flew military jets in test flights across the continental US mimicking the routes that any SST -- US or otherwise -- would take and found the public wouldn't wear it. We found that out too during the west Britain supersonic test flights, but by then it was too late -- we had already spent the money. Everyone knew what a sonic bang was -- it is simply amazing to behold that no one had thought that part of it through. Condemned to flying over Mach 1 only over blue water, the economics were completely screwed.