It's not even worth it to say why or how, since not even doing rudimentary research means that you aren't interested in developing a well-informed opinion.
That's just false. You might try to rule it out yourself to see. My comments here and the responses demonstrate that it's a waste of time to argue against people in the purity cycle of global warming. My position is one of moderation not denial - and I'm downvoted, told I don't care, and I haven't done even the minimum of research. Pffft. HN is not what it used to be.
You've heard of the saying that extraordinary claims require extraordinary evidence? Holding a hypothesis of water-vapor from air travel being the primary driver of warming trends is extraordinary.
Invoking the oft-repeated "do your own research" rhetorical crutch and referring to scientific consensus as "hype" doesn't help your case.
Do you have any reason to believe otherwise besides a couple of anecdotes about looking at the sky and short-term temperature variations?
Have you calculated the water vapor generated from air travel, and compared that to the water vapor already generated by the water cycle? (just normal evaporation from lakes/rivers/oceans/plants)
Even as back-of-napkin math, this should be a pretty easy sanity check.
I think you're off by a few orders of magnitude here, but I also don't want to discourage you from adopting a "check for yourself" mindset.
I've SEEN the effects with my own eyes. You can also see contrails seeding cloud formation on some days. Then there's the fact that these extra clouds are formed and dissipate on a 24 hour cycle, so part of the day they let in sunlight and part of the night they trap heat. These effects are significant and there is little research on the bigger picture effects of this (that I've seen).