4 ms·The X-15 has recorded 7,274 km/h airspeeds. I'm no airspeed record expert but did some reading.by mrhyyyyde 5y agoThe X-15 has recorded 7,274 km/h airspeeds. I'm no airspeed record expert but did some reading.dogorman 5y agoThe X-15 was a rocket.mrhyyyyde 5y agoJust because it has a rocket engine, that doesn't mean it's a "rocket", it's a rocket-propelled aircraft.