The US Air Force is getting near the testing of an unmanned aircraft, a hypersonic weapon fly at least five times the speed of sound.

The weapon is being developed is based on an experimental scramjet or Supersonic Combustion Ramjet program. According to NASA, in a scramjet the oxygen needed by the engine to combust is taken from the atmosphere passing through the vehicle rather than from an onboard tank.

Researchers anticipate that scramjet could reach 15 times the speed of sound. For example, an 18-hour trip to Tokyo from New York City becomes a 2-hour flight.

Though scramjet, army aircraft traveling at that speed could reach targets before they’re detected.
In 2013, Defense Tech reported that the ‘Air Force Sees Hypersonic Weapons in 2025. The same year an experimental ‘scramjet’ made by Boeing called the X-51 WaveRider reached up to five times the speed of sound for a record three and a half minutes. That was called the longest air-breathing hypersonic flight ever.

Air Force Research Laboratory and DARPA, the Pentagon's research arm are working on a hypersonic air vehicle that can travel at speeds up to Mach 5, which is five times the speed of sound while carrying guidance systems and other materials.

In an interview with Military.com Air Force chief scientist Mica Endsley said, "Certainly, the US is not the only country involved in developing hypersonic weapons. The advantage of hypersonics is not just that something goes very fast but that it can go great distances at those speeds”.