Indeed.
I've got a F award ticket booked HND-LAX-BOS. When I booked it, both legs were in Flagship F. With the downgrade to a 2-class plane for the domestic leg, will I be able to use the Flagship lounge? I've got a layover that's just under 12 hrs and was hoping to be able to use the quiet room for a nap if needed between the flights. If not, I'll see about booking a day room at the Sheraton, I suppose.

Certainly, you can use the FL, which is allowed for same-day itineraries that include international J or F. You can even use FFD based on your arrival in international F. Your domestic class of service doesn't matter in this case -- it could even be Y.

Well, they are buying the 321XLR for TATL routes. The speculation is that it will be equipped with J/W/MCE/Y and used on thin Euro routes from JFK and PHL. Perhaps something like 12-16 J and 8-12 W. If that's the case, with enough birds they could also alternate them with TCON runs. For example, PHL-Europe-PHL-LAX-BOS-LAX-PHL and so on. Depending on the timing it could also improve aircraft utilization. Similar if they are used for MIA to thinner routes in South America, they could alternate through MIA-South America-MIA-LAX-BOS-LAX-MIA....

What about the 757s they use on MIA->JFK and JFK->EGE

As someone else said, you should have access to both the Flagship Lounge and Flagship First Dining by virtue of your inbound international F flight. That said, you could also request a switch to LAX-JFK-BOS, with the former in F, on account of the schedule change. Depends on how much you value the lieflat seat and enhanced meal service vs. the convenience of a nonstop.

Actually being based in NYC and flying to the west coast quite often, I disagree that American is " an ultra low cost airline". In fact my company only contracts with American for their business class product both on the ground and in the air. And many times I will use a SWU which gets me into the FFD dining area at JFK and LAX. Hardly an ultra low cost experience in my opinion....

"Lots" is subjective. AA has a fleet of 34 757's, and only 10 of those have 12 lie flat seats up front. The remaining 24 have 16 standard (i.e. not lie flat) domestic business class seats.

For all the "cheapness" people complain about AA, I wouldn't even begin to put them into the ULCC category by any stretch. When they shut their lounges, gut the Advantage program and leave OW and any other airline partnerships, then we can talk about whether or not they have earned ULCC status in the race to the bottom.

I was under the impression that the 757s are being phased out (because of fuel efficiency/maintenance costs) but don't have any facts on it.

Actually, the 16 J seat 757s are lie flat.

To add onto it, the 12J LUS 757s are not fully lie-flat, as they only recline at ~170 degrees.

AA's issue with BOS flight to me is the price -- while DL UA and B6 sells BOS lie-flat cheaper than JFK lie-flat (and sometimes there's $499 oneway up front to BOS), AA prices BOS flight ridiculously high in comparison (~$800 oneway on 32T I fare) and this just does not make sense to me not flying DL/UA/B6 if I have to spend my own money.

Actually the 12J LUS 757s all have domestic F seats and are used primarily for PHX-Hawaii runs. The US-era Envoy recliners (not lie-flats) are now gone.

Thanks for the clarification. I had it reversed. Not sure I would still consider 24 lie flat 757's "Lots".

Denied From QF F Lounge
 

I've been let in several times on a LAX-BOS in J. I think the issue is you were an arriving passenger connecting on a non oneworld airline. I don't believe you have access in that scenario.