I always understood that Mary was a house maid at the Rothchilds mansion in Switzerland and that she was knocked up by a Rothchild. She had to be sent away afterward.
Flight time:13min, and altitude: 5800ft do not match up.
Payload = 330,000lbs JP4 fuel, each. Extended flight time would indicate a lot of airborne sorties needing fuel. If they stay up that long.