The other day I watched a plane leave a trail at 10:05 in the morning in Sartell, MN. I left the job site at 10:30 and watched it grow. On the way there were other planes with both kinds of trails, some that maintained and others that dissipated. Even while I was driving along I would watch other planes go through this cloud and their trails would dissipate, but this one would not. I would upload a pic but that option doesn't appear available any longer. I followed this all the way to North Minneapolis where we had to stop and go to work, total air time for this cloud formed from this plane was from 10:05 am till 12:37 and still going strong. Then I thought, I take brakes apart, paint without respirators, rip apart ceilings and expose myself to some ungodly fumes that I shouldn't, so whats the beef? I am sure they are trying to do something if this original post is correct and global dimming cooled us, then they would only think in this way, dim the planet again but with a healthier substance than smog.