A declassified document was recently found in the National Archives that featured a VTOK aircraft that was being built for the Canadian government in 1952 by Avro Aircraft until they found it too expensive. In 1955, the U.S. Army and Air Force decided to pick up the tab on the vehicle that had a wing span of 18 ft., a height of 4 ft. 10-inches and a weight of 4,620 lbs.. The ultimate goal was to build a hovercraft capable of reaching a speed of Mach 4 (2,880 mph) and a height of 100,000 feet (19 miles.)
Needless to say, the project was scrapped in 1961 when a model of the VZ-9AV Avrocar with turbojet engines uncontrollably rolled when tested above 3 feet and only hit a speed of 35 mph. The vehicle is now in the USAF's National Museum where all can lament its demise or appreciate it as a fine example of military intelligence during the Cold War.