OK,Rocket Safety Inspector w/Masters in Aeronautical Engineering,State's the Contrary,To what I've seen!I've never seen a Contrail from an Aircraft,Leave a Residual Plume,As Long a Time,As this one did,& The reason why Aircraft Plumes don't last too long is the mixture of air intake with the Fuel!Rocket Engines Use solid Rocket fuel,& If Air is introduced,such as on an Intake port,The Rocket will Explode,hence my theory,of which wasn't explained,:Long Lasting Residual Plume!