Reasons for it being an aircraft:
1) no US missiles fired from the area according to NORAD and US Navy;
2) meterologist claims conditions permit optical illusion giving the appearance of a missile launch;
3) speed of object may not track as a missile; and
4) no sonic boom recorded or witnessed

Reasons for it being a missile:
1) contrail mimics those of other rockets;
2) ballistic arc to contrail shows range and height;
3) towards end of video, the object displays what can be described as the rocket exhaust - something not possible if it was an aircraft - where you normally don’t see such exhaust at distance

I haven’t seen any related items noting the witnessing of a sonic boom so that potentially mitigates against it being a missile, but given the distance involved that may not have been heard.

On balance, I’m leaning towards a missile or rocket of undetermined origin. It could be a secret DARPA style project along the lines of a hypersonic vehicle. That could explain why no one at NORAD is able to confirm - it’s a black project and they can only confirm that it wasn’t a threat to the US.

Still, the possibility that it was a unknown entity that fired the object that close to the US coast and no one seems to know who or what it was is disconcerting to say the least - especially if it instead of arcing out to sea it was fired at, and hit, somewhere in Los Angeles.