Read up on the Bond-McKaskill Act, I don't think you'll like the implications. Both NWA/DAL and CAL/UAL SLI's were completed without participation of the respective companies, and in fact all the surviving airline (DAL & UAL) management had to do was "Accept" the SLI as arbitrated.
The American/USAir case will be an entirely different animal IMO.
First, there are 3 different unions representing the 4 merging pilot groups. DAL/NWA and CAL/UAL were contentious enough merging under a common policy, but this merger obviously doesn't have that.
Second, Under Bond-McKaskill if the representing unions can't agree to an SLI, the company is required to participate. This will be a test case as it's not been done on such a scale and with as many participants. There is an opinion that if unions can't agree, that the company could impose a solution that it deems "fair and equitable".
...McCaskill-Bond establishes that it is the duty of the surviving or combined carrier to provide the fair and equitable seniority list integration process. The carrier can satisfy this duty by accepting a voluntarily negotiated or arbitrated list from the employee group parties. To the extent that the employee group parties do not voluntarily present such a list to the carrier, however, it is the carrier's duty to engage in arbitration with those groups as provided for in Section 13. If the covered transaction involves employee groups represented by the same union, the statute provides that the union's internal merger policies apply exclusively, with no carrier involvement, except as to whether it will accept and implement the result of the integration process (i.e., the combined seniority list). Likewise, any additional LPP or other merger-related requirements in a CBA that are consistent with the "protections afforded by" Sections 3 and 13 are not directly affected by the statute.
One thing for sure, it's going to be a bumpy ride.