Experiments in weather modification are not really that secret, you can read all about them. The Chinese have offices of weather control in each province.
https://en.wikipedia.org/wiki/Beijing_Weather_Modification_Office
this is a pretty good explanation of why you sometimes you can see the vapor trails and sometimes you can't:
https://www.scientificamerican.com/article/why-do-jets-leave-a-white/
@funbobby51 yep absolutely right.....its not so covert or secret anymore. Even MSM has been reporting on this (though in a disinfo distorted fashion) for atleast a decade. It is colossal foolishness to ignore such enormous amount of evidence.
Jet travel is pretty popular, so people don't care about the environmental impacts.
Well jet travel and chemtrails are not the same... jets can and Di contribute to stratospheric pollution but the fumes from it are mainly water and co2, which dissipates rapidly.
Chemtrails.. as I discussed here, are different and deliberate, not a byproduct of jet flight. It doesn’t even come out if the engine emission, it has sophisticated spraying mechanism on the planes
And the airplane mechanics are unaware or all in on it?
@funbobby51 there have been whistleblowers out of the team of pilots engaged in such spraying. I have shared one such video of a USAF pilot in this post.
I watched the one with the girl who wanted people to send $50 to a secret laboratory.
@funbobby51 - whats your opinion of it?
Beijing Weather Modification Office
The Beijing Weather Modification Office is a unit of the Beijing Meteorological Bureau tasked with weather control in Beijing, China, and its surrounding areas, including parts of Hebei and Inner Mongolia.
The Beijing Weather Modification Office form a part of China's nationwide weather control effort, believed to be the world's largest; it employs 37,000 people nationwide, who seed clouds by firing rockets and shells loaded with silver iodide into them. According to Zhang Qiang, head of the Office, cloud seeding increased precipitation in Beijing by about one-eighth in 2004; nationwide, similar efforts added 210 cubic kilometres (7.4×10^12 cu ft) of rain between 1995 and 2003.
The work of the Office is largely aimed at hail storm prevention or making rain to end droughts; they have also induced precipitation for purposes of firefighting or counteracting the effect of severe dust storms, as they did in the aftermath of one storm in April 2006 which dropped 300,000 tonnes of dust and sand on the city and was believed to have been the largest in five years.