I read a lot of these chemtrail articles and there have been a few where they claim to have done various sampling and found increased levels of barium and aluminum. There is one poster here who posts some pretty good ones. I read another that claimed to have photos of the chemtrail planes but they were all just regular firefighting and crop dusting planes, one had a logo of the company and I looked it up and they were an aerial spraying company and they had helped with various firefighting and insect killing missions and operated several aircraft with scary looking tanks inside.
@starangel has the best chemtrail posts because they don't get all defensive when you ask questions and such and they have some pretty cool links to various patents and government documents that are pretty fascinating.
I posted a link somewhere on here to a debunking (or at least a claim of such) of the video that was posted. Apparently the testing done in that particular case were not aerial samples but samples from the bottom of a pond and the aluminum levels were consistent with what is found naturally occurring in your average dirt. I would be curious to see some studies that included samples taken directly from the trails. I don't think I have seen any but that doesn't mean they don't exist. As with all studies, the devil is in the details.
I just get frustrated when I see people post things comparing a tea kettle to a con trail (for example). It's arguments like those that give conspiracy theorists a bad name. Some people take to these theories as if it were a religion and based on what is often rather flimsy evidence. I'm willing to believe these trails are something nefarious but it's going to take more than a tea kettle comparison and a study of pond muck to convince me. Sure, I'm extremely skeptical of everything government says (though I don't recall them making much in the way of pronouncements about contrails) but I'm also skeptical about every conspiracy theory I hear unless there is something to substantiate them beyond conjecture, bad analogies and questionable correlations.
the term "conspiracy theorists" was invented to give conspiracy theorists a bad name ;)
I find the evidence for Donald Trump's time machine more compelling than the contrail conspiracy at this point but I am open minded. That poster does post some very cool patents to some pretty wild technology that does exist.