Chemtrails in Helsinki

I was riding with the bike yesterday, a wonderful Summer Sunday. Going towards Helsinki I see a plane that is passing in the sky, following the same path of another plane already gone by. The trail that the first plane left behind was still visible, I thought it was just passed and that was the 'normal' trail made by planes. Also the second one was leaving a white compact trail. I again thought it was normal. Once got close to Helsinki, around 30 minutes later, I turned my bike over to go back home. Surprise surprise the trails were both still there, the first one was expanding and second was still compact though starting to expand. "Trails that last for so much???" The connection in my mind was straightforward. No please, not also here...

Update for who doesn't know what chemtrails are (or are supposed to be) here you can find some explanation:
in english
or
in italian