Aircraft experts and military aficionados have cause to rejoice now that Lockheed Martin has debuted the SR-72 unmanned spy plane, the long-awaited successor to the SR-71 Blackbird and potentially the first hypersonic craft to enter service. Plans for the SR-72 drone were first unveiled Friday in an Aviation Week article which revealed that Lockheed Martin’s Skunk Works advanced development program... 

Arcing through the hazy air above California, this is the incredible sight of a scramjet as it flies at six times the speed of sound. The experimental aircraft set a record for hypersonic flight, blazing through the air for more than three minutes at Mach 6, or more than 4,500 mph. The X-51A Waverider scramjet was released from a B-52 bomber last week before its engine took it to Mach 6 and it flew...