I actually printed the poster from STOP CHEMTRAILS (note that using all caps tells you for sure that the site is reputable)
http://www.stop-chemtrails.com/posters.html

and put it up in my office. hehe. Anyway, notice that the obviously photoshoped aircraft on the poster



I mean, is there anyone who honestly can't see that it's been photoshoped? If the people you're arguing with can't see that for themselves, then go to walmart and buy them a $20 pair of binoculars. If they like looking up so much, they should at least be able to see what it is their looking at. Through binoculars, it's pretty obvious that contrails are comming out of the aircraft's engines, and not from sprayers on the wings.