One of the makers we encountered setting up for the Maker Faire Detroit on Friday afternoon was Douglas Amick. Amick was unloading the A2, a three-wheeled, battery-powered, wind-assisted tandem-two-seater. The A2 was originally built by Amick's late father, James, who devised the aerodynamic arch on the rear of the vehicle. That element is claimed to help propel the vehicle forward in crosswinds.
Apparently, airflow coming in at an angle to the vehicle will swirl around as it passes through the arch, actually applying force to the A2's rear, giving it some boost. We'll have to check with some contacts with aerodynamic expertise on the veracity of this claim. Regardless, the Amick A2 is kind of cool-looking. Apparently, it originally had aluminum air batteries installed but they're no longer functional.