I landed at JFK yesterday, just after 12 noon. As we were taxiing to Terminal 7, we passed a plane taxiing towards the runway. A 747, painted completely white, no other colours or marks at all. No windows except on the UD. It only had some small letters painted at the front, beginning B-... . Is that B for Belgium? And why no windows (a freight plane?), and why no other paint job. It looked like the kind of plane that comes from PIK full of men in orange boiler suits.