Is that the Aurora or whatever it was called, that story in the late 80s/early 90s? I can recall stuff like ‘it had a contrail like donuts with a string through the holes’ and it made a pulsing ripping noise or something.
Freegards
The X-51A Waverider is an unmanned scramjet-powered demonstration aircraft, capable of achieving hypersonic speeds five times the speed of sound. At that speed an aircraft could travel across the U.S. in under an hour.
http://roadrunnersinternationale.com/transporting_the_a-12.html