Yes, they are. All you have to do is look up. One day the sky is blue. The next day it's crisscrossed with chemtrails. They're so obvious, they're disrupting radar weather maps.
Who is doing it and why?
It appears to be a multiple-purpose operation: 1) climate modification; 2) weaponzing the atmosphere, and 3) making tons of toxic coal ash - the byproduct of coal burning plant - "disappear."
In short, a lot of government-enabled and protected criminals are making a fortune out of this.
The video that talks about the how and why of chemtrails, the second one in the series as made by this guy.