Flying H,

I live in the same general direction as you, not quite as far north. My choice has been United/Star Alliance. Good destinations out of IAD and plenty of connections via ORD out of DCA, and BWI has a decent range of UA options as well. And guessing from your use name, the new ( season) direct from IAD to EDI may be a nice plus. Having a carrier with decent service to all three airports has been very useful to me when plans change or flights get cancelled ( just don't expect United to automatically understand that changing from IAD to DCA is an OK choice).

PS why won't Southwest accept WAS a valid flight search code - hate having to try each airport separately :-(