How about if you describe in greater detail what you saw?

You said it was about 3:57AM. That is very helpful.
It rules out a number of possibile things that might be
seen near sunrise or sunset.

You said that from where you was standing, it was heading
east-northeast. Can you say roughly where you were in the
LA area? In which direction did you first see the thing?
(Either a compass heading or direction to a landmark.)
In which direction did you last see it?

Did you have to turn to follow it accross the sky?

Did it change direction at all, or did it move in a
straight line?

How high in the sky did it appear? In degrees above the
horizon (90 degrees is straight up), or hand-widths above
the horizon. See this web page for info on estimating
height above the horizon (or "altitude") in hand-widths
(halfway down the page):

http://www.cloudbait.com/science/fireballs.html

What was the altitude when you first saw it? When you
last saw it? When it was at its highest?

How long was it visible? A couple of seconds? A minute?
Five minutes?

What shape was the object? Was it a pinpoint like a star
or planet? Was it round or elonglated in the direction
it was moving?

How big was the object, in terms of angle? If you hold
up your little finger at arm's length, it will more than
cover the full moon. Was the object wider than that?
Wider than your thumb? Wider than your hand?

Did the object look sharp-edged or fuzzy?

How bright was it? Compare the brightness to something
you could see from the same location at the same time,
such as a streetlight that you know is a mile away, or a
lighted wall or billboard in the next block.

What color or colors did it have?

That should pin it down fairly well.

-- Jeff, in Minneapolis