Aircraft contrails have been around in aviation, since before World War II. Common occurrences, during World War II.
Atmospheric conditions and certain body shapes (traveling within a range of velocities) passing through a set of such atmospheric conditions, produces the contrail(s).
The contrails witnessed, usually do not indicate a purposely measured release of some liquid and/or gas - being released from a dedicated tank within the aircraft fuselage or from a pod, attached.
A contrail is not at all dependent upon such a release.
So, the notion of: “Look! They are releasing _____!” . . . is imaginary - because, without certain visual aids, the human eye is not going to see if “some liquid and/or gas” is in the contrail.
The logistics of one or more tanks/pods, are most often overlooked by observers who fear the contrails. From the ground, observers see a long, long contrail, and they assume that is caused by released liquid/gas. When, a measured release would be nothing like what the eye beholds - given that the release would be measured to blend in and be un-noticeable by people on the ground.
Again, you cannot know, if there is something being dispersed at high altitude, without certain visual aids.
“The Party told you to reject the evidence of your eyes and ears. It was their final, most essential command.” --George Orwell
Search images of “contrails” and “battle of britain”.
Overhead, both sides are spreading condensation during “dogfights”.
My GOD!!! Stop. We all know what a f’g contrail is. Some flyboy please explain why the one in the video stop like that, like a switch was flipped!!!