Assuming that the union doesn't want to get fined out of existance, I would think that they would wait until they have a final court ruling that UA breached the contract BEFORE starting any job actions - and getting such a ruling could take all summer.

The FAs need to realize that their glorious union, through a series of incredibly stupid actions (passing on the ESOP, signing a 10 year contract, etc) has left them with about zilch as far as bargining leverage. If the union starts this CHAOS nonsense without a ruling that UA has breached the contract UA will go to court for a finding that the FAs are in breach. Once they get such a finding they'll declare the contract void, lock everyone out, and then offer a solid raise with a US Air waiver clause as a condition of return. And I bet 50% of the FAs will cross at that point. Then you cut the schedule back for a couple of months as you run whoever is interested from the recently graduated high school classes of Iowa and Nebraska through the system.

Look, UA is going to settle with the mechanics soon; if the FAs start any kind of job action they're the ones that are going to be without a chair when the music stops.

Of course, I'm sure that based on the high level of support the FA union gave the pilots and is giving the mechanics they'll refuse to cross a few minutes after hell freezes over.