Wow, thanks for all the reponses! I'm from DC and I would imagine that I'll be traveling domestically primarily. Because I'll be using Dulles Airport, I thought about JetBlue might be the best choice. I'm not quite sure exactly how much I'll be traveling, depending on what my work decides to do with me, but it would be great if I can use my frequent mileage for intercontinential travels, which means JetBlue might be a bad idea. Does anybody know if Southwest and AA fly to other countries? (Asia and Europe)