Ask any Coincidence Theorist, and they'll be sure to regurgitate one of their favorite claims: The term "chemtrails" is an unscientific and unprofessional term invented by internet wackos to try to drum up paranoia surrounding a phenomenon that isn't happening and is merely the product of wild imaginations. There's a problem with this television-supported theory about the etymology of the word, however. The earliest known use of it appears to be from the United States Air Force itself, in 1990.
"Chemtrails, chemistry 131 manual, fall 1990" is the title of a pilot training manual from 1990 produced by the Department of Defense. According to Veteranstoday.com columnist Harold Saive, the content of this manual "suggests possible methods for manipulation of the earth’s atmospheric chemistry and conductivity, and could be construed as a course requirement for pilots who could be engaged in deploying chemicals into the atmosphere."
Regardless of the context of the term, however, this revelation clearly destroys the common claim that the term "chemtrails" is merely an internet buzzword with no relation to reality. It is a term which appears to have originated from our own government years before the internet was widely used. This discovery also severely damages the dubious claim that chemtrails are indeed real, but being used by the "good guys" in government to counteract the effects of global warming. Global warming theory was still a hotly debated political issue in 1990, making the likelihood of a government funded program to combat it seem premature.
Here's a link to the Veteranstoday.com article: http://www.veteranstoday.com/2013/10/30/documents-reveal-chemtrails-orig...