The Department of Defense started using "cirrus shields," aka chemtrails, during the Vietnam War to make high altitude reconnaissance and special operations aircraft undetectable by ground observation. The idea that persistent contrails only appeared after 1995, and, therefore, photos of these trails pre-1995 prove they are only water vapor trails from jet aircraft is a fallacy I would expect to find in a forum run by someone without a science or military background.
Additionally, many of the photos posted have captured cirrus fibratus clouds, which are easily mistaken for contrails by the untrained eye, and contain neither contrails nor chemtrails.
What is especially ridiculous is to think the readers of this forum won't realize that an actual contrail made by a jet aircraft traveling 6-7 miles per minute during the 1960s is incapable of producing a very long trail in a photo that took only a fraction of a second to capture.
Also, the southwest, where most movies were filmed, is more arid than locations in the mid-west or east, causing the air above to be cold enough to sustain visible water vapor trails much longer than usual.