If anyone thinks the PBGC is averse to absorbing more pension plan obligations, I am not easily convinced. The PBGC gets all the real money and gets to use math magic to rewrite the new amounts owed out (for pennies on the dollar). The only possible down side for the PBGC is the need to hire too many mathematicians too quickly to rewrite too many plans at once.
The real issue at play regarding the pensions is many times greater than the pensions themselves, IMHO. Did the LAA unions agree to keep their pension (yet frozen) in exchange for giving up the profit sharing that LUS unions had? A short term preferential benefit for a select portion of the employees (the ones getting to make the decision to give up what others had) in exchange for a theoretically unlimited benefit to other employees (the ones that were excluded from the decision that cost them).
The frozen pensions at LAA are miniscule compared to the Profit Sharing that was abandoned. But perhaps the promise to save what was left of the LAA employee pensions was more beneficial to them than the money in LUS profit sharing, and more beneficial than the possibility of negotiating a similar profit sharing for all new american employees.
United, Continental, Delta, Northwest, and USAir all lost their pensions. LAA didn't get to keep their pension for free....
Things are rarely as they first appear.