A few things to consider when pondering contrails.....
1. How much fluid would the aircraft have to carry in order to spray a continuous stream on your average 800 mile flight.
2. How much space would this take up on the aircraft, and would it be feasible to conceal this?
3. What would the concentration of this chemical be at ground level after being sprayed? Is it feasible that it would provide a substantive dose of anything?
Given the fact that schoolkids have been making "contrails" in a bottle for years(
), and that all aircraft will make short duration contrails at the wingtips under the right conditions, isnt it far more likely that there is nothing going on?