Warned2, for starters look up operation Indigo Skyfold.  It is from 2015 but will give you some idea of what our Air Force has been up to for several years.  Also look up Solar Radiation Management Program run by the CIA, it costs the American taxpayer 156 BILLION dollars a year (2017) to run the program in North America. In July of 2016 John Brennan admitted that the CIA was involved in these stratospheric aerosol injection SRM programs at a CFR conference.  The reason the Western governments refuse to discuss it, is that it is intended to be a Top Secret Activity done  cooperatively and covertly without taxpayer knowledge.  I guess we must be too sottish to understand the true benevolence of the Deep State.    Fortunately, in more recent years many people have finally started to notice and ask questions.  My question has always been why don't they want us to know?  It must be very bad if they have to hide it from us.  There is no question that chemtrailing is a government activity that really got going during the Clinton administration.    If you remember looking at the skies in the 1980s or earlier if you were born then,  you will remember that there was no such phenomenon. One way to know if its a chemtrail is that it does not dissipate it only dims the sunlight in a haze that spreads across the sky.  You will notice the blue skies become fouled within just a few hours.  On the other hand a REAL CONTRAIL is water vapour from combustion exhaust gases which turm to microscopic ice crystals which then reflect sunlight and become visible, and appear white like a real cloud.  However, the ice crystals that form the VISIBLE contrail soon SUBLIMATE and disappear after exiting the turbofan engine within 1500 to 3000 feet.  This is a fact with both High Bypass and Low Bypass turbofan configurations.  If you see a visible trail that extends for several miles beyond the aircraft you will know for certain that those are NOT ice crystals.  Due to the extremely low relative humidity at elevations of 24,000 feet and above, it is impossible for ice crystals to not sublimate quickly under those conditions, it is simple physics. Another observation to make which you can see for yourself is on some unexpected day, (I noticed usually on some Saturday mornings or midweek in the midwest) when there are NO chemtrails in the sky and there are nice white puffy clouds in a clear BLUE sky, don't assume that jets are not flying that day, they will be much more difficult to find, but just take the time to locate jet aircraft by listening and looking up and see for yourself the real contrails dissipating soon after exiting the turbofan exhaust. The contrails all look the same as they quickly disappear within a minute or two at the tail end of the contrail. If you are wondering, part of my background has to do with aircraft science and engineering in addition to aircraft powerplant design particularly those beautiful GE tubofans.  Best of luck in your researches.