That may change in the near future; I suspect that, unless Virgin America collapses unexpetedly, they're going to be a major force in the US market. All they're lacking to really do damage is a feeder system into the midwest. Their planes are wonderful, their service is different enough to separate them from the rest of the crowd, and they seem to want to be offering pretty decent pricing at the moment (and, surprisingly, without much reaction from the rest of the industry, which will likely change soon).

If Virgin America flew to places I need to travel, I'd likely be saying buh-bye to UA. But for now, the midwest, hawaii & France keep me with UA.