The larger prototype will fly as high as 55,000 feet and manage its supersonic speeds despite running on just one of the two engines you see in the F/A-18 Hornet. In practice, it could cut the flight time from New York to Los Angeles in half, to 3 hours.

NASA has already outlined plans to fly the finished aircraft by 2020 (including over populated areas), and already has funding for the first year of its 5-year roadmap. This isn't the same as a passenger aircraft, alas, but not to worry. The organization plans to hand out the knowledge from its tests to private manufacturers, some of whom (such as Boom Technology) already have plans for supersonic passenger jets. It won't happen for a long while, but there should be a day when a flight across the country no longer chews up most of your day.