Jet Plane Smoke Lines in the Sky

Its all water vapor that freezes, nothing dirty about it. as H20 is a byproduct of burned fuel. Our cars would do it too if it were -40...We have Vandenburg AFB up the coast and we see the rocket/missile contrails for 1-2 nights at a late sunset. Very nice to see those, like little stars flying up slowly if you catch a launch in the eve.