Back in 1984, Craig Henderson and Bill Green built a one-of-a-kind super fuel-efficient car called the Avion. In 1986, it set the Guinness world record for fuel economy by averaging 103.7USmpg (2.27L/100km) while driving from the Mexican to Canadian borders. Unlike most autos from that era, the Avion is still on the road... and breaking its own records. In October 2008, Henderson and Green achieved 113.1mpg (2.08 L/100km) on a 263-mile (423 km) trip in the US Pacific Northwest. Then, this August 29th, they departed from Blaine, Washington (adjacent to the Canadian border) and drove 1,478 miles (2,379 km) to the Mexican border. They used just 12.4 US gallons (46.94 L) of diesel and set a new record of 119.1mpg (1.97L/100km).

In highway tests prior to this latest cross-America trip, the current incarnation of the Avion has managed a reported 80mpg at 70mph (2.94 L/100km at 112.65km/h), and 114mpg at 55mph (2.06 L/100km at 88.51km/h). On this trip, said Henderson, they averaged 55mph. They did stop to rest at night, but never refueled – on reaching Mexico, there was still approximately 6.1 gallons (23.09 L) of fuel in the car’s 18.5-gallon (70.03 L) tank.

The Avion is powered by an 800cc, 67hp diesel engine. That engine is transversely-mounted behind the two seats, in a monocoque 6061 aluminum chassis. The outstanding fuel economy is due to an aerodynamic lightweight design, low rolling-resistance tires, and a body made from lightweight composites including carbon fiber, Kevlar and "S"-Glass. Only three to six horsepower is required to maintain highway speed, which gives the car a top speed of over 100mph (160.93km/h).

If you’re thinking that you would like an Avion of your own... it’s in the works. Given that the car will reportedly be hand built in a limited run, however, it probably won’t come cheap.