Delta pulled its non-stop from Indianapolis to Washington National. That was predictable; it acquired the route when it bought Northwest, and Indianapolis was never integral to Delta's route system. My first few tickets this year on now-monopolist U.S. Airways exceeded $400, 33% higher than what I had been accustomed to in a duopoly market.
Then I saw some non-stops advertised by United. They weren't price competitive; United wanted $381, my US Airways flight was back down to a not-too-far-from-normal $333.
Today the United flights are not listed (I'm looking on Orbitz), but U.S. Airways is charging well less than $300.
Perhaps bolstering my view that this is a negotiation between United and U.S. Airways, there was a United Airlines 747 on the ground in Indianapolis yesterday when I flew out. That might be (slight exaggeration here) the first passenger 747 ever to taxi to a gate in Indianapolis. More likely, of course, a plane from Chicago to Paris needed hydraulic fluid.