I was under the impression that it would be a sort of a lifting-body design.

Looking at the admittedly beautiful and curvaceous shape of that aircar, I see very little in it that would generate any lift. To get lift, you need some sort of airfoil shape. This is always more efficient (in terms of drag) than powering a flat surface at an angle of attack sufficient to provide enough lift to remain airborne. The term lift/drag ratio refers to how much drag you incur for x amount of lift. Generating lift causes induced drag that, while not really the same as pure aerodynamic drag, still requires energy to overcome. The more efficient a shape that a wing (or lifting body or, for that matter, a brick) has, the less power it takes to generate the lift required to remain airborne. I see lots of drag compared to the amount of lift in the Aircar's design.

tanstaafl.

"There Ain't No Such Thing As A Free Lunch"