I'm talking about stuff like this, to grab the first images google finds, some right off the morons own sites.

http://www.thelivingmoon.com/46ats_memb ... rail01.jpg
http://imageshack.us/photo/my-images/14 ... il5xq.jpg/
For a long time, like 1990 or so, morons have been claiming that contrails like this are proof of a pulse detonation engine equipped aircraft flying around at mach 5, because look the puffs must be pulses! Too bad for these people any plausible PDE that can maintain supersonic let alone hypersonic speed would have thousands of pulses per second and would logically make nothing like this sort of contrail. However such claims did at least show up hand in hand with reports of Aurora as an SR-71 replacement, which at least had people with some level of reputableness backing it up.
The chemtrail stuff is just utterly without any basis at all and was started as a deliberate hoax in the mid 90s. The raving idiots who believe in chemtrails will point at any contrail and suggest its a government plot to poison the earth and engage in simultaneous weather and mind control.