George Barris' X-PAC 400. Basically, it was a simple hovercraft. It was designed with a plenum chamber that, when filled with air, allowed the car to float a few inches off the ground. Barris built small thrusters into the sides which allowed it to be steered, after a fashion. But it was never highly functional as a vehicle; instead, it was the simple, confident futurism of its upswept fins and low-to-the-ground profile which made Barris’ air car a hot rod show favorite.