The two main reasons supersonic flight hasn't caught on (other than the late, great Concorde) are the amount of fuel it takes to achieve such high speeds and the deafening, potentially destructive sonic boom that occurs when crossing the sound barrier. Well, NASA has a gorgeous new concept plane that addresses both issues.
The Supersonic Green Machine, designed by NASA and Lockheed Martin, features a new inverted-V "wing" over the tail section that's meant to both increase energy efficiency and decrease the noise created by a sonic boom. So could this be the plane that lets us fly from New York to L.A. in an hour? It's certainly an exciting thought.