Sinclair C5 with Sinclair claiming that he had found "very big" levels of interest. Hoover were sufficiently persuaded to allow Sinclair to divert 10 of their employees to modify C5s for overseas export. The bid to sell the C5 abroad failed; the Dutch National Transport Service told Sinclair that the C5 was not suitable for Dutch roads without improvements to its braking system, the addition of more reflectors, and the inclusion of the High-Vis Mast as part of the basic package. Most of the other ten countries that Sinclair inquired of demanded similar changes. The C5's reputation received a further battering when
Personal air vehicle breakthroughs. A ground transport alternative is enabled by unmanned aircraft technologies: Autonomous Systems and electric propulsion. Barriers include aviation safety, airworthiness, operating costs, usability, airspace integration, aircraft noise and emissions, tackled first by small UAS certification then experience. Other names discussed include PIVITOLs (Personal Vertical TakeOff vehicles), Air-cars, PACs (Personal AirCraft), AVs (Air Vehicles). The first technical paper to explain the difference in vehicle characteristics between PAVs and existing General Aviation single engine piston aircraft was "Personal Air Vehicles: A Rural/Regional and Intra-Urban On-Demand Transportation System" by Mark D. Moore (the NASA PAV Sector Manager) from NASA Langley Research Center.