First thing to do is to find out what your rights are.

Often times an airline will take extra steps for a customer.

Try this to start with. Look at conditions of carriage.

http://www.aa.com/i18n/aboutUs/customerCommitment/main.jsp?anchorEvent=false&from=Nav

First, you should check your itinerary again. Last non-stop flight ORD-BOS on 11/22 is the 8pm AA1358.

Anyways, what happens depends on why that flight is cancelled. Airlines don't cancel due to low loads, but there's also mechanical and weather. The REALLY SMART thing to do is to get travel insurance. Whenever you get a cancellation late in the day, DON'T WAIT FOR THE AIRLINE to help you. Go book an airport hotel right away. And use the airline's phone agent (unless there's a massive weather problem like Sandy) rather than line up at the customer service in the airport.

Claim whatever is owed you later on. That way you won't be sleeping on an airport floor, hungry and everything.

BTW, I'd have taken the JL non-stop on the 787 definitely. Save a lot of hassle with immigration and reclearing security at ORD, and worry about missed connection and everything else.

BTW, let's say you are on the 8pm and it gets cancelled for whatever reason, you cannot forget getting home that night. That is the last non-stop on ANY AIRLINE. Previous flight would be a 6:34p on UA for 11/22. This is not a route with hourly flight.

That's really weird, especially since there IS a 10 PM flight ORD-BOS on Nov 23 (arriving 1 AM on Nov 24) that is also numbered AA1358!

What are your flight numbers and days?

Airlines change around schedule during holidays.

So it appears that if the OP is really on a 10 PM flight on AA, it isn't on Nov 22.

Sorry ...I rechecked and it is not a 10 PM flight it is an 8 PM flight. (2000H). Either way, it is the last flight out on AA. So I guess travel insurance makes the most sense. Sheesh. Any recommendations?

Keep in mind that it's unlikely the 8pm flight would be canceled: airlines are especially loath to canceling last flights of the day, as it screws up their personnel repositioning as much as it inconveniences customers.

That said, uour flight from Tokyo is scheduled to arrive in Chicago at 3:35. You could make a 6:35 flight on United -- you'd need to have AA endorse your ticket for that flight.

If you learn that the 8pm ORD-BOS flight will not operate when you get to Narita, see if AA will endorse your ticket to the excellent Air Canada connection (via Toronto) that departs at 5pm. Delta also has a bunch of options to BOS, leaving at 2:45 (via DTW), 3:05 (MSP), 3:00 (SEA), and 3:30 (ATL). Be very wary if they offer you a connection on AA through LAX: it could involve a 13-hour layover in LAX, plus the red-eye from LAX to BOS.