The chemmies themselves cannot agree on the purpose/method/logistics of supposed "chemtrails".
They are an inchoate disparate rabble united only by their ignorance of science, meteorology, aviation and a deep paranoia. They are not freethinkers. They are a cult in the worst sense.
Some will tell you about contrails being covert Geoengineering. None of them have read the relevant proposals about geoengineering, or have applied them to what they believe. The proposals stress that any sulphate release would be in the high stratosphere, and within 30 degrees of the equator. Tell that to them and watch the blank uncomprehending looks.
Tell them why the aircraft we fly cannot perform that mission and be prepared for the same reaction that a happy clappy will give you when you question their beliefs.
It is the same mindset.