[Rokke]

"You mean like this shuttle launch video where it appears to be going pretty slow and the contrail is twisted, broken up and widening fairly fast at the base in less than two minutes?"

Cool video. You realize it was filmed from 38,000ft and in just over 30 secs the space shuttle had climbed well above the altitude of the aircraft from which it was filmed (and didn't slow down from there)? And while the contrail was twisted, it was never broken that I saw, and the last time the base was shown (35 secs after launch) it hadn't widened at all. For that matter, the exhaust trail of the largest missile we launch remained very narrow and distinct during the entire length of the video. Nothing like the contrail pictured off California.

[TigersEye]

Near the very end of the video he pans down for just a second and there is a huge break in the contrail. Here are two more shuttle launch videos that show just how fast the contrail can expand and distort even on a dead calm day. They also show how different a contrail from the same vehicle can be on two different days.

Real Sound of Space Shuttle STS-117 Launch, 3 miles

BEST SOUND OF A SHUTTLE LAUNCH! STS-117

Found another shuttle launch video where you can "see" it break the sound barrier if you want to see it. It has no relevance to contrail appearances.