Oh, hell yeah. Totally a design exercise. One of the biggest problems the B-36 had was a lack of landing strips; as I recall, there were only a handful that were hard enough to deal with its weight. B-36 loaded weight: 260,000 lb. C-5B loaded weight: 760,000 lb. This turkey: Twelve. Million. Pounds. Never mind that the USAF gave up on nuclear planes in the early '60s. Never mind that the hottest-shit engine of the time, put out a paltry 50,000 lbs of thrust. Let's put together a design exercise that will tow five 737s and relies on 625,000 lbs of thrust just to keep it from falling out of the sky. somebody paid for it, though. I've got a bunch of paper on the Boeing 2707 and while it was kind of pie in the sky, too, Boeing was deadly serious about it. The cancellation of the 2707 was the proximate cause of ten years of economic depression in the Seattle metro area.