Thank’s for adding the new contrails effect ! They are super nice. My only feedback is the drift direction.
Actually the plane seems to go in a different direction than the contrails. They are following the wind direction and go out the plane with an angle (exept if there is a perfect font wind) but in the real life they appear straight beehind the plane then the entire drag move with the wind direction, as a cloud.
I think it’s quite easy to fix and it would improve a lot the reality !
It looks to me like the contrails don’t drift, as they should (as the OP describes). The contrails need to be stationary in the air mass, not stationary relative to the ground.
Hopefully it is possible to make them drift in the air mass so this can be fixed.
If you watch the Live Q&A, this is only the first stage (and it even stated this on the Developer Patch Notes during the download of Sim Update 3) of contrails. Things like drift and the ability to see other simmers’ contrails are coming later.