Have you not bothered to check the facts? Why do conspiracy theorists assume the worst instead of finding out the truth?
https://www.aerosociety.com/news/chemtrails-debunked/ will help you, unless you have already made up your mind.
A condensation trail (it's
not a chem trail) will be dispersed at a rate determined by atmospheric conditions. Have you not seen how some long trails are disturbed along the length at some point? It's where high level winds interact with the condensation trail. Commercial aircraft try to fly with the high level winds known as the jet stream. In Australia, flying east to west can be much longer than west to east. Contrails are dispersed almost immediately.
Jet fuel is high grade Kerosene. The exhaust from a jet engine is no worse than any other exhaust and cleaner than diesel exhaust. It was once common to see a lot of smoke from jet engines on take off. This is due to inefficient combustion. Modern engines are much better designed. It's purely a matter of economics. Fuel efficiency means more money in the airline's bank.
Governments have much easier ways of reducing the population. For instance, make the cost of living so high that couples quit having children.