Or maybe the glider could have been released from a ship in the Black Sea? Al Qaeda has a number of ships.
ships...that's something that has always bothered me...I remember their ramblings...they are wanting to do something at sea, block a canal, crash into a terminal, a seaborne attack at a resort...cruise ships..
I still think the sea has been overlooked as a threat, but walking across the border with Mexico is still probably easiest...