"Of course odd contrails are very much of interest to those people looking for the exotic propulsions, such as Pulsed Wave Detonation (PWD), which has been long associated with Black projects such as the famed Aurora."
Much controversy remains of this unacknowledged aircraft - some believe the Aurora is really a UAV...
Much more and lots of relevant hyperlinks at: http://www.memes.org/modules.php?op=modload&name=News&file=article&sid=1389&mode=thread&order=0&thold=0
For models based on eyewitness reports of the Aurora, see: http://aurorapage.tripod.com/
Click on the word 'THIS' in the first paragraph when you get there.