Do you have any hard information on that? Any links to credible sources regarding those claims? I am the first one to be suspicious of the gov't, however I am not so sure about this claim. No offense at all, but it seems to very far fetched.
The white tail/trail you see coming from the back of Jets are called Contrails, it is perfectly normal for those to be white, and spread out like a cloud, depending on the atmospheric conditions at the time the jet flies through. It has been like this since Jets have been flying in the upper atmosphere. Contrails are condensation trails (sometimes called vapor trails): artificial cirrus clouds made by the exhaust of aircraft engines or wingtip vortices which precipitate a stream of tiny ice crystals in moist, frigid upper air.
The this link: