AirTran started flying IAD-MCO nonstop a few months ago, so B6 would have some competition in a market that's pretty low-cost to begin with. I don't know if it's some sort of "gentleman's agreement" between two LCCs or just market factors, but I can't think of a single city pair where AirTran and JetBlue compete nonstop, head-to-head. The two carriers tend to complement each other's routes very well, i.e. from RIC B6 goes north to JFK and BOS while FL goes south to MCO and ATL (with connections to everywhere in Florida).