THIS IS THE "DARPA" created, US Air Force "Blackswift Rapid Strike vehicle". It has a Turbin Ram Jet HTV-3X engine. It is expected to be capable of Mac. 6
(6 times the speed of sound). That is: at sea level and 20 degrees C. / 68 F it is: 7,416 km/h and 4,608 mph. What is often not spoken off is that at 60,000 ft. the speed is close to twice of that in relation to the ground, because the air is so much thinner. The aircraft has to travel so much faster to travel through the same amount of air - to create the same power / thrust. That is like from the USA to Europe in 30 minutes - - - -