I think he understood the issues integrating UA were above his head, and his statements show he has a view labor relations issues there were uniquely deep and not repairable by him. Witness the pilot action in 1999/2000 at UA.

When he consulted for Delta investors on a merger the reco was United, though if I recall the closest thing to near-reality was Delta and Continental merging and fell apart last minute. Much closer cultures there but less network benefit.

http://dealbook.nytimes.com/2007/11/...r-with-united/

The big strategic hurdle was that 'golden share' Northwest held in CO after DOJ action in the early 2000s. It basically meant NW would find a merger partner first, as NW had veto power over any CO tie-up

http://usatoday30.usatoday.com/trave...est-pact_x.htm