Baltimore?
BTW, one of those places is the Manassas Regional Airport about 14 miles from here. They actually have Arab operated taxicabs serving the area.
It's my guess several of them managed to get there and then end up in suburban DC and in Baltimore with friends of their families, or relatives in their extended families. Probably arrived with advice to "Be sure to call Aunt Alia" along with her phone number.
SO far none of these guys have gone anyplace that can't be explained as "lost". Now that could be part of a plan, or they could be lost.
Although Manassas has no regularly scheduled service, it's not that hard to get a hop to take you there from major airports up and down the East Coast. In fact, "this is the major reliever airport for Dulles International Airport and Washington National Airport.
A reliever airport is one that accepts smaller, private aircraft so that the major airport can focus its capacity on airline operations.
Because Manassas Regional has four flight schools, Manassas has a large amount of training traffic. Training operations account for approximately 50% of our yearly operations, with the other 50% being corporate traffic."
There's that flight training school deal again ~ maybe some of them knew an Egyptian terrorist there eh?!