According to France24 this is normal water vapor from airplanes flying in a grid pattern and chemtrails are a debunked conspiracy theory.

First of all these clouds don't evaporate they sink and spread out, creating a sheen like oil on water.
Second, airlines fly in dedicated routes.
Third, during one particularly heavy chemtrail operation near San Antonio International I was working outdoors when one of these planes made an emergency landing with smoke trailing from a bad engine. The aircraft was an all white 4 engine airliner with only a small N number and all passenger window shades down.
I hate the MSM