Unless I'm mistaken (a common occurrence, alas) the answer to that is sometimes "no," so I'm not sure it qualifies as a goofy question. You can't enter class A or class B airspace without permission. You can't land or taxi at a controlled airport without permission. You can't land on just any private airfield without permission. Perhaps pilots flying in and out of the D.C. might also have a different view of that question.