A patent for "altering a region in the earth's atmosphere"

Of course, the existence of a patent is not direct proof but in conjunction with other bits of evidence is highly indicative.

Of course, if you are invested in NOT believing something you never will.

US Patent 4686605 - 

Operation Chemtrail

1. Technical Field

This invention relates to a method and apparatus for altering at least one selected region normally existing above the earth's surface and more particularly relates to a method and apparatus for altering said at least one region by initially transmitting electromagnetic radiation from the earth's surface essentially parallel to and along naturally-occurring, divergent magnetic field lines which extend from the earth's surface through the region or regions to be altered.

https://patents.google.com/patent/US4686605A/en