(I love this thread)
Well, as crazy as it sounds, it could actually work as a kind of once-in-a-life-flying-experience. Just imagine the ac rounding the world with stops in major cities and then in each one of these just a one-hour (sightseeing) flight. If they charge, let's say, 100 EUR or USD per pax (with beverage, peanuts, leaflet, diplom...) and you multiply 100 x 1.000 = 100.000 EUR-USD per flight, it could work. Just imagine: Monday-Berlin, Tuesday-Amsterdam, Wednesday-München, Thursday-Zürich, Friday-Sat-Sun-Paris... The fact of being the only one, the biggest, the unique, the beast... would attract many people and media attention (for free), I presume. Even the cabin noise or an old-fashion interior wouldn't hurt the bussines case.