May 2007. Their pilots, still under separate contracts, can't figure out how to merge seniority lists. The ALPA, representing both groups of pilots, has an arbitrator figure it out. The old USAir pilots don't like the result.
April 2008. Old USAir pilots vote out the ALPA, replacing it with a union who's constitution says it will fight for the seniority system they want.
Old America West pilots get pissed and start acting out.
Now: the new union sues its own members under RICO.