One of the first things I heard was this “thing” was traveling in a westerly direction. Was the flight from Hawaii traveling west as it approached Los Angeles?
It was moving east, and not very quickly from the video (in which most of the “movement” is an optical illusion from the camera bouncing and the digital optics trying to make sense of the few-pixel image being zoomed in on from long range).
It only looks like it’s “moving west” because you think the contrail has to be closer where it is larger, like those illusions where you think the guy is really big or really small because you think the room is square.
The contrail is bigger further away, because it is spreading out over time. The “start” of the contrail isn’t coming from land, it is over the horizon.