In the 1960s, the Boeing Company's Vertol Division released advanced designs of two helicopters being studied for inter city and airport to center city transportation. A major feature of the two new helicopters, according to Boeing engineers, was that operating costs per seat mile were tp be about half that of helicopters then in service. The model 157B (shown here) was to be an extended version of the U.S. Army Chinook and would have carried up to 55 passengers at a cruise speed of 200mph. Powered by two Pratt & Whitney J FTD-12 engines, the 157B would have had a gross weight of 41,000 pounds. It was scheduled to be available in 1968.