The CNN article For 747, transporting a shuttle is no heavy burden shows the shuttle Discovery on top of a "shuttle shuttle", a special 747 used to shuttle the space shuttles around.
How close to the White house did it fly? Did there need to be any special arrangements to fly so close to this highly sensitive airspace (especially post-9/11)?
Note: Presumably this is a NASA aircraft rather than a military aircraft (e.g. Marine 1) so the flight planning for this "fly-over" may not be exactly the same as those for landing a helicopter on the White House lawn.