Three parallel rows of trail, evenly spaced. About a year ago now. One plane did one row, turned around and did the second row. A second plane did the third row.

I don't know what they're doing. I do know I haven't seen any announcements from the government saying that they're starting such-and-such a programme. My working theory is that they're experimenting. Maybe directing the path of an air mass eg making it turn left on demand. Typically we will get rain two days after they spray.

https://www.geoengineeringwatch.org/
Dane Wigington has been running this site for years apparently. Lots of info, I haven't dug into it.