What would they debate? They both have one-track, non-converging minds, one that can only focus on LCC's world domination, the other on DL's. Parallel tracks; not much to debate.
The only issue I can see them having any debate on is, "When UA tanks, which it inevitably will since it sucks so bad and is the worst ickiest airline ever in the history of the world, who will get the Pacific routes, LCC or DL?" They both seem to have had a lot to say about that over time.