And now we know that J-Man didn't pass basic chemistry. Pray tell me, what do you think are the combustion products of jet fuel and oxygen? It's helpful to not assert things like "contrails were created by water in the engines for cooling" or "Today's jets rarely use anything that could cause a contrail" when it's obvious you haven't the slightest clue how a jet engine works (and neither do I, but at least I know what they take in and spit out).
Do you see how often conspiracy theorists don't even know the basics about how things work? Of course, they love dismissing quotidian explanations and then cooking up some outlandish garbage.