Huh, yeah I think that's maybe the Virginia delegation's favorite airport but I'm highly skeptical it is for other members as it's pretty far and while it does have more flights, I don't think it's incredible. For international flights when traveling for work, many Congresspeople will use milair anyways. For reference, I worked as a staffer in Congress for a couple of years and just picked this up although I've never done any in-depth research
