The most visionary flying luxury liner was Norman Bel Geddes' 1929 design for an "intercontinental airliner of 1940." Bel Geddes, together with German-trained aeronautical engineer Otto Koller, envisioned a plane to carry 451 passengers or about twenty times the capacity of existing planes. It would offer accommodations, he later wrote, "equal in spaciousness and comfort to the most modern ocean liner." This was no idle exaggeration, since the crew of 155 included a librarian, gymnast, masseur and masseuse, two headwaiters, two wine stewards, seven musicians, and nine bar stewards! More than two hundred people could dine simultaneously in the plane's main dining room, and 150 could look out from chairs on the promenade deck. Interestingly, although Bel Geddes and Koller made bold and detailed plans for services and accommodations, they showed a certain timidity about the plane's mechanical functions. Their behemoth would fly on twenty engines, but the designers included six more "in reserve," anticipating that some would fail in flight and require repair or total replacement, to be made possible by motors mounted on wheels for easy movement and substitution. Compared to the 195-foot wingspan of the Boeing 747, today's largest airliner, the Bel Geddes seaplane would have been a giant with its 528-foot wing. Visions like Bel Geddes' giant flying wing, although economically unrealistic and technically naive, nevertheless anticipated the mass transit, public carrier nature of travel in the mature aviation age.