Since the merger of USAirways and American Airlines, flights from LAX have been moved to Terminal 6 – previously occupied by United and still by Alaska. United has moved its flights out and created space for US to use 6 gates for its flights. When US was located in Terminal 3 – you can read about how the old connections worked in this post. There is a bus service in addition to the tunnels.
So fast forward and at the same time as moving to T6, LAX re-opened the tunnels that run under the tarmac and link Terminals 4, 5 and 6.
The tunnels allow airside access between the terminals used by American, Delta and USAirways as well as Alaska which operates codeshares for AA. You access the tunnels at Terminal 4 adjacent to the bus gate which links Terminal 3 to Thomas Bradley for International flights as well to the American Envoy commuter flight terminal.
Down the escalator:
you reach the tunnel, illustrated with aviation facts from history
It is about an 8 minute walk to Terminal 5 where you can exit, about another 5 minutes and you are in Terminal 6.
The corridor to Terminal 6 is a lot more boring:
Then it is time to exit the tunnels:
You come up in T6 towards the back of the terminal so have to allow about 3-4 minutes to get to the USAirways gates.
If you can secure access to the Alaska Clubroom (Priority Pass accepted) it is located on floor up from the terminal.
It is worth noting that you can walk airside between Terminal 6, and 7 & 8, used by United.