Why hasn't SWA added more flights in and out of Dulles? I think it is kid of surprising I though SWA went in there to compete with United more then they did?
I don't think WN goes into any market just to compete with another carrier. They go where they think they can make money. That said, the last year+ has been a time of holding on for about every carrier and WN is no exception - I think more places saw a reduction in WN flights than saw increases last year.