I live in northern virginia and have flown out of both Dulles and regan with cased firearms (handguns and longuns) with no issue. If you originating your trip at regan be sure to get there a little earlier than normal. When you check in you tell them you have a fire arm. They will get a TSA agent to inspect your firearm, case, and integrity of the locks. Some times this take a minute or two, sometimes you get an overzealous TSA agent that may call over others to make sure your good to go. This one time took me 15 minutes. Just check TSAs website for case and lock requirements and you should be good to go