CanadianCripple said:how do you know? who's to say what would propel a 'real ufo'? lol
anyway, it's actually an unmanned fighter:
http://www.darpa.mil/ucav/photos/sixthF/ED02-0295-05b.jpg
That's cool shit bro,that thing looked trippy from underneath.Without that vapor trail,I would be shitting looking up at that,lol.