Most of the stuff put out by the truther crowd is deliberate disinfo. A trail's persistence has nothing to do with whether it's a contrail or a chemtrail. That still does not mean stuff isn't being sprayed into the atmosphere for any number of reasons. It only means that it will only be visible under the same atmospheric conditions that normal vapor trails appear. So they very well could be spraying and you don't see it. I believe the chemtrail phenomenon is real. I know what non water vapor trails look like, and it has nothing to do with their persistence, but rather their overall appearance. However, there is nothing natural about alleged "vapor trails" that linger long enough to expand and eventually cover the entire sky with a pseudo cloudcover. Chemtrails often look oily and have a driplike appearance. You can also sometimes see a rainbow effect from whatever is in the spray. In areas of heavy spraying, a white web-like material has been collected and found to contain heavy metals like aluminum, as well as biological agents, like dessicated white blood cells. This is not normal by any stretch of the imagination.