[RiK]

The planes only leave persistent vapour trails in areas if the sky where wind, temperature, dew point and humidity allow at the altitude they are cruising regardless of what's in the fuel ? These factors all vary during the course of even an internal flight .
I thought the idea of "spraying" was to have control of the trails and how long they last . How much of a particulate such as aluminium whatever could you add to a fuel to treat 100 miles or more of sky , and have it burn efficiently in the engines ? There are still those who say it's sprayed from hoses .
After seeing a few videos and writings on the subject , I'm not convinced about "chemtrails" .

Ice age documentary looks interesting .