The Aerocivic apparently has a distant relative from Canada. Darin Cosgrove, founder of Ecomodder.com, has added a boat tail to the back of his 1998 Pontiac Firefly (which is what the Geo Metro was called up north). According to Wired, the modified bodywork was constructed from cardboard, aluminum and duct tape, and it joins a series of previous aero mods including rear wheel skirts and a bellypan.
Back in the spring of 2008 when General Motors took us on a tour of its wind tunnel facility, chief engineer Frank Weber emphasized the importance of aerodynamics in maximizing the electric driving range of the Volt. At that time, all we got see was a one-third scale model covered in various colors of duct tape. However, GM's aerodynamicists, including Nina Tortosa, explained that even at lower speeds, resistance to air-flow played an even bigger part in efficiency than the car's mass.