Automakers have been interested in aerodynamics at least since the introduction of the Chrysler Airflow in 1934. But the need to improve fuel economy in recent years has pushed aerodynamics toward the top of automakers' priority lists.It turns out we — the car-buying public — have helped cause this emphasis on aerodynamics. You see, the easiest way to improve a vehicle's fuel economy is to make it smaller and lighter and give it a smaller engine. But we want 400-hp sports cars and seven-passenger SUVs and 5,000-pound-capacity tow vehicles — and we want good gas mileage, too.

Lucky for us automakers have found a way to do that: by making their vehicles slip more smoothly through the air.

"The main driver for lower aerodynamic drag is fuel economy," says Max Schenkel, General Motors technical fellow, aerodynamics. "As long as federal standards for fuel economy increase and fuel costs go up, aerodynamic drag will have to be improved."

Automakers focus on aerodynamics for financial reasons, too. "Aero benefits can almost be cost-free to some extent — just how you bend the metal and how you execute gaps and joints, and…a lot of that is design," says Rick Aneiros, Chrysler Group's vice president of Jeep and truck design. "If you're trying to reduce weight by adding expensive exotic materials, that's not easy to do. And improving engine efficiency, that's not easy to do. So the leading strategy is to improve aerodynamics whenever possible. That's why we built our own full-size wind tunnel here."

In fact, today's wisdom says you can't start measuring a vehicle's aerodynamics too early in the design process. From the earliest conceptual stages on through the working-prototype stage, automakers rely on computer software and wind tunnels to ensure vehicles meet their aerodynamic targets.