US Air Force was able to push a sled(with superconductor magnets to lift/rockets to thrust) at 633 mph

@WarfareWW #USAF was able to coast a sled(with superconductor magnets to lift/rockets to thrust) at 633 mph pic.twitter.com/VtLGHuGYiZ

— Warfare Worldwide (@WarfareWW) April 24, 2016