Just was in my backyard and noticed these strange aeroplane trails. Five or six jets flying randomly and leaving those trails that do not disappear after a while. Most of them over my city. I saw them before, but never really thought about it. After quick Internet research I've learnt that they are some sort of chemtrails. I'm not some conspiracy type, but it's strange that it started in 2000, just after we joined NATO. What you guys think, is there reason to be worried?