Are you seriously asking, or are you trolling?
Looks legit from a little searching, the picture, not the chemtrail conspiracy.
The government doesn't quite have its stuff together. I doubt they could mess with something like that without anyone knowing. They don't have better things to do than spray down the population from the sky?
https://en.wikipedia.org/wiki/ContrailLooks like the plane's moving upward and if it weighs tons it would use a lot of fuel and produce a lot of water vapor out the back. Add the right weather conditions and the sunlight hitting it just right. Voila... that pic.
Or it's an elaborate government conspiracy to control the population. And they're doing it with commercial airliners in plain ("plane") view for decades but nobody's bothered to investigate it.
You've even got the answer in your quote...
"...This theory is not accepted by the scientific community, which states that they are just normal contrails, as there is no scientific evidence supporting the chemtrail theory."
Tineye the pic. There's a site that has more oddball jet liner pictures. Things look weird in the sky. I'm not posting the site though since I got a fake virus warning popup on it.