More than a century ago, the first aviation pioneers figured out a way to use rigid wings with flaps to generate enough force to lift a heavy craft into the sky. It was one of the great advances in human history and also the beginning of a new era in transportation. Airplanes, and the airline industry that depends on them, are now among the world’s largest businesses, with air travel producing over US $700 billion in annual revenues.
However, commercial airlines spend more than 25 percent [pdf] of their operating expenses on fuel, earning the industry a reputation for razor-thin margins that will eke out just $39 billion [pdf] in profits this year. Meanwhile, modern aircraft wings and engines have reached near-peak levels of efficiency, making it exceedingly difficult for engineers to generate additional savings.