Don't quote me on this, I'm sure there are guys here who know a LOT more than I do about this, but I don't believe the RLA or the McCaskill-Bond amendment will allow an airline to just purchase another just to get rid of it. The seniority lists are required to be merged, if either airline holds a FAA certificate. Someone can correct me if I'm wrong.

Furthermore, I don't believe the DOJ would allow AA to purchase Spirit, since AA is the world's largest airline and the acquisition and merger would be seen as anti-competitive, especially now given the fact that American is changing rates and stating that Spirit is competing with them across a large portion of their domestic market.