There were some threads over on PlaneBusiness a few weeks ago talking about crews on layover. Basically, you're out of luck if you're not at home. AA will immediately cancel all crew hotel rooms, so FAs will be out on the street. Apparently in '93, AA also informed immigration in Brazil of the illegality of some of the FAs who were marooned there during the strike. They didn't have proper documentation (passports) to be there, so they were arrested.
Other airlines will not allow striking employees to fly standby. The only option left is for FAs to purchase tickets and fly home, at their own expense. I'm sure this could get pretty expensive - buying a last minute international ticket.
I think the message board said that the union was going to allow FAs to work flights back to the US, to help allieviate some of these problems. But, they'd only be allowed to work until they got to the first US city. So, if you were in London, you could fly to JFK, but you wouldn't be able to continue working a flight to your home in LA. You'd have to "join the picket line in JFK where your fellow strikers would welcome you" or something of that sort.
d