Uber’s eyes are on a new prize: flying cars. Outlined in a white paper published this week, the company’s chief product officer, Jeff Holden, describes a network of small, electric aircraft that can take-off and land vertically (VTOL, or vertical take-off and landing, aircraft) to enable speedy and reliable commuting that it claims will ease congestion in cities. Uber doesn’t plan to build any of these “flying cars”, but has produced a plan called Elevate…