Mackdog
Senior Member.
I wanted to share this because I think it could be useful in debunking, and I didn't know what thread to put it under, but it is video of aircraft exhaust being sampled by a NASA Falcon 20-E5 aircraft. They are taking samples of particulate matter in the exhaust of a DC-8 and also the ice crystals of the contrail. There may be data out there on the samples, but I have not had time to check yet.