At some point of me life I lived in Carmel, just a bit south of Monterey in California. The airspace above this section of the Cali coast was absolutely riddled with chemtrails every day during the summer I was there. I used to hear a lot of the older hippie-heads rambling about this subject over coffe and spliffs every morning.
I was interested until I did a bit of research and realized the airspace above Carmel is one of the most populated in the world. Being a major intersection for flights at all altitudes, going to and from every single major and minor airport in the world.