You guys specialize in being wrong. I am 72 and saw contrails when I must have been about 4 years old. They were undoubtedly B-52s on test flights from the Boeing plant in Seattle. Like chalk streaks across the sky. I also live south of a major international airport, and they are as common as clouds (and the Pacific Northwest is noted for clouds).

The reason that people didn't talk about them much until the 1990s is because it was only about then that passenger jetliners were flying close to 40,000 feet or higher. At those altitudes, the air is colder, depending on latitude (i.e., tropopause height). And at lower pressure, so the saturation vapor pressure would be much lower, and ice would stay frozen much longer. Military aircraft commonly flew at 50,000 feet, so it was no mystery that they would always generate contrails. On a very noteworthy summer at the University of Washington, a Fraternity brother and I noticed a contrail that was proceeding across the sky at an unusual rate. Trying to measure the angle rate and guessing the altitude was military (i.e., 50,000 ft), we estimated the speed as being about Mach 2+ and concluded it must have been an SR-71. That would have been the early 1970s (they entered service in 1966).

The "chemtrail" hypothesis (not analytical enough to be a "theory") is simple fancy. The proponents (like you) declare they know all about contrails, and you really don't know anything but falsehoods. You also don't like people who have credentials in the relevant fields, but that also comes with the false egalitarianism of the internet. You don't like it when experts apply their expertise, because the expert wannabees show up badly.

What I am saying is consistent with both the graph you presented and the other website. You are the one having the trouble making sense out of them. You simply don't understand what they mean.

The air has some water vapor content even at high altitude, albeit very small. The saturation vapor pressure is very low, close to zero on the arithmetic scale, but present nonetheless. The water vapor will freeze. If the temperature is cold enough, it will attain a temperature below freezing---and the vapor pressure of the ice crystal will be very low. (The vapor pressure is one 10,000th of sea level pressure at -50 C.) Low enough that it may take a very long time for it to dissipate, or possibly not at all, since clouds of ice crystals will have their own local atmosphere saturation high in water vapor. (Cirrus clouds, for example, can form as high as 66,000 feet, and they hang around for a long time. Contrails are only artificial cirrus clouds.)

Do you really know that airplanes are at the same altitude, or do they only appear to be at the same altitude? There will be a transition altitude where contrails will prevail. At altitudes below 20,000 feet, they generally do not form.

What you are seeing are contrails and your "bullshit" claim is itself bullshit. Your attempt to prove they are not is a failure, since you don't understand what you are looking at. The upper air is mostly at saturation humidity---which is a very LOW humidity. That's the part you don't understand. And if the ice gets down to the air temperature, it is so cold that its vapor pressure is very, very LOW. Just consider frozen ponds. They have a vapor pressure. Why don't they just go away by sublimation? But they don't. They persist. Because the vapor pressure is so low, the process is very slow. Antarctica is nothing but ice. According to your hypothesis, it should never persist. Tell that to Antarctica.

Here is the great problem of the Awakening: a little bit of knowledge and a huge dose of mistaken belief are almost insuperable obstacles to waking up to reality. You are there on the front lines. Have sympathy for the poor jerk who doesn't get all this conspiracy stuff...or the poor conspiracy buff that doesn't want to give up his paranoia.