Chemtrails. Just Another Conspiracy Theory?

While hiking through the woods, I am having a Rachel Carson “silent spring” moment. It’s early fall, nature is still beautiful, albeit a bit dry. There are no birds chirping, no squirrels, no snakes, just an annoying horse fly and a few mosquitoes. The fern gully is bone dry; all ferns have turned rusty brown from lack of rain. I finally spot a few small fishes darting about in the yellowish creek water. The sky is blue for now but crisscrossed by grey and white trails that don’t disappear at all like vapors do but dissipate and blend hours and hours later into a strangely colored mist with blue-grey edges that blanket the sky. What is this? Why are the trails so perfectly parallel in both directions and intersecting like a chess board? Why would a plane maneuver in this grid pattern if it’s flying the shortest distance possible to a specific destination?