The contrail itself would be wider at the earlier in time position, due to wind dispersal. So the appearance depends very much on the angle at which the object is observed, and the actual vector of the object. Hard to know any of it, although smarter guys than me should be able to come up with a good idea of the flight path given that we know the position of the helicopter and the direction of observation.
To me, it’s a rocket launch, plain as day. No way this wasn’t picked up on radar either. Somehow, everyone knew it was 35 miles off the coast.
It was big, and it’s being hushed up for reasons unknown.
Take a look at the screenshots here: http://losangeles.cbslocal.com/gallery/2010/11/09/mystery-missile-launch-off-california/#photo-1
To me, the spread of the contrail/plume to its left at it's trailing edge looks like what I'd expect to see a half hour or so back the line on a persistent airplane contrail. It doesn't look like what I'd expect it to look like a couple minutes back on a smoke trail.