My neighbor is a senior AirTran type. He's not a union insider but he knows them all. He passed along the following rumor:

He says the AirTran people are mostly just sitting back and watching.
The Southwest pilots are starting to develop factions based on seniority. They are pretty much negotiating with themselves right now and the fear of what an arbitrator will do is driving them to make concessions to themselves.

Meanwhile, the AirTran merger team is methodically preparing for the hearings.
They're confident. They believe their case is strong.