There's a reason why the Concorde only flew over the Atlantic Ocean: sonic booms. If every aeroplane were supersonic, it'd be extremely noisy and annoying. Fortunately, NASA is working in a solution.
NASA is working on multiple experiments to develop an aeroplane that will not boom like Steve Jobs in a keynote. If they achieve their objectives, it will solve one of the problems of civilian supersonic flight. It will also make planes look like flying narwhals. And we are OK with that. [NASA]