Check this out... blows my mind. it has now been revealed that the US Air Force at the same time launched an experimental hypersonic glider able to travel more than 6500km in 30 minutes from launch. http://www.couriermail.com.au/news/...-a-faster-aurora/story-e6frer8x-1225858361350 top speed: Mach 20 (21,000 km/h or ~13,000 mph)