1. UA now has two hubs cheek-by-jowel (in air miles speak). That's not sustainable long-term. But, one is NYC and the other is the nation's capital.

The EWR hub hurts UA badly because it's way downscale for the corporate customers they crave. But, UA can't ditch the NYC market and it has no real presence at JFK.

Same for IAD. Govt. contracts and govt. contractor + foreign investors flow through IAD.