<i>NASA teams also collected data on the volume of sound made by XB-1 on the flight route.</i><p><i>Boom says its analysis has found that no audible sonic boom reached the ground during the flight.</i><p><i>Minimizing sonic boom has been a key goal for engineers involved in the race to bring about the return of commercial supersonic air travel.</i><p>That's interesting. Could anybody explain how they actually managed to do that? I always thought sonic booms were just this quirk of physics that is more-or-less unchangable, is their method of supressing such booms just flying higher, or is there some technology advancement that allows for this?