Tuesday afternoon, I was enjoying the fact that I can now enter the terminals and do some exercise (i.e. walking the terminals). At approximately 1730Hrs while I was in Terminal B, I looked out and noticed the traffic backed up, waiting to take off on 18L. One particular aircraft caught my eye; it was an all white 737-200 or 300, with no tail markings or logo, and the only markings was the registration number on the side of the aircraft, near the tail, and what appeared to be a two line airline designator on the side of the aircraft, just behind the cockpit (it was below the halfway point of the side of the aircraft, or about 60% down from the top line of the aircraft's profile). I was just too far away to even read the lettering for the airline designator. Obviously this is probably a charter aircraft, but does anyone have any idea what airline or company flies with this paint scheme and small black lettering for airline designator? Regards, Richard p.s. Sure was nice to give the attendant my parking ticket and see $00.00 displayed on the "Amount Due" indicator :-)