What you are seeing is the natural crossing of flight paths. There is a lot of aerial traffic, and we seldom hear the sound. I live next to an international air terminal and they are common. Zero humidity on the ground does not translate to zero humidity at high altitude. And what is really crucial is the relative humidity, not the absolute humidity. If the vapor pressure of water vapor is higher than the vapor pressure from frozen ice crystals, the crystals will not sublimate into vapor. This is a very low vapor pressure.

I've observed persistent contrails in a clear sky when I was a toddler sitting in my back yard. The only aircraft that could do that were B-52s on test flights from the Boeing factory in Seattle where they were constructed. 50,000 feet altitude. So it is simply untrue that contrails always dissipate in 2 or 3 minutes. They are clouds and they will persist as long as a cloud can persist, quite some while. Your 2-3 minute persistence requirement is sheer myth.

A persistent contrail will unwrap and spread, becoming more diaphanous. I've seen that recently. That's a pretty stupid concept of spreading anything, that it would stay in place at high altitude for hours and not descend.

As for what a whistleblower might say, we have no substantiation of his claims. I reserve the right to be doubtful because I have already seen hoax material coming out of the "chemtrail" camp. There is a strong element of ignorance and deceit in this camp.

And contrails are not produced by heated air. They are produced by water vapor in the jet exhaust that is frozen solid upon exposure to ambient atmospheric conditions. In other words, it is a cloud just like the other clouds at that altitude. The clouds persist. No reason for a contrail not to persist if the relative humidity is 100%.