As with pretty much all jetliners, the 747 has seen its fuselage stretched (and shortened) to adjust the number of passengers and other payload it can carry. But as stretched as it has been, there were plans for much more extravagant changes. In the early 1970s there were plans in place for not only fuselage stretches by way of inserting lengthening plugs, but also by stretching the upper deck much further aft, turning it into a true double-decker. As the diagram below shows, for shorter routes the passenger count count be bumped up to 1000. keep in ind that this was using 1971-era seating; with modern 21st century passenger-packing technology, who knows haw many human bodies could have been stuffed into these planes, ready to be driven mad by booze, low oxygen, screaming babies and deep vein thrombosis.
