After the 2003 concessions, it may not be so much a pay difference as it is a benefits/productivity difference. The available info says that average employee pay isn't out of line - just slightly above the average for the network carriers. But average pension/benefit cost was nearly $5000/year per employee above the next highest carrier and nearly $6000/year/employee above the average (which includes AA) in 2010. The DB pension plans are obviously a large cost that none of the competition has. F/A's, for example, being able to fly relatively little yet keeping full benefits is a productivity cost. Since I know nothing about all the groups contracts, I'll leave it at that.
Jim