Southwest Airlines announced that it plans service from Washington-Dulles airport beginning this fall. I usually don’t bother with new city announcements, but Southwest has changed its strategy so significantly in the past couple of years that it warrants a mention. Southwest used to actively avoid competing directly with other low cost carriers, preferring to stay out of their way and carve out underserved routes with high fares. But since their entry into Philadelphia and Denver, they’ve decided to fight low cost carriers head on. And Dulles is no different–JetBlue has a number of flights from the airport. In fact, this move suggests that JetBlue is not the unstoppable juggernaut it once was. It’ll be fun to see if they compete head-to-head (I’m guessing they won’t).