Airplanes do not look much like birds. But, according to a pair of engineers in California and South Africa, a bird's design could make an aircraft more fuel efficient.

The modern airplane design works well, but from a fuel efficiency standpoint, could planes be designed more aerodynamically -- to lower drag and increase lift?

This kind of airplane design could be a boon for carriers as they are always at the receiving end when oil prices spike. Currently, crude oil futures were trading at $85 a barrel.

Geoffrey Spedding, an engineer at the University of Southern California, and Joachim Huyssen at Northwest University in South Africa, felt they could in theory, but they lacked experimental evidence.

But, now they have the all important experimental evidence.

Spedding and Huyssen have made a simple modular aircraft in three configurations: a flying wing alone, then wings plus body, and then wings plus body and a tail.

They started with a configuration where the entire plane is one big wing. Then they added a body designed to minimize drag and, most critically, a small tail, which essentially serves to undo aerodynamic disturbances created by the body.

The two engineers have analyzed the airflows and at various relative angles for the wings, body and tail, searching for ways to achieve greater lift for carrying cargo and lower drag for better fuel efficiency. They made the stipulation that for any given mission, the best plane is the one that generates the least drag.

The flying wings alone provide an ideal (but impractical) baseline, since it's hard to carry people or cargo in such a shape. The presence of a body, unfortunately, immediately lowers the lift and increases the drag. The addition of just the right kind of tail, however, can restore the lift, and reduce the drag, occasionally to nearly wing-only levels, the engineers say.

Spedding recognizes that the design of real planes is necessarily a compromise of many engineering, economic and psychological constraints. Nevertheless, he believes much can be done to make planes more energy efficient in the future.

The most important point is that we may be wasting large amounts of fossil fuel by flying in fundamentally sub-optimal aircraft designs, says Spedding. At the very least, we can show that there exists an alternative design that is aerodynamically superior. One may argue that there is now an imperative to further explore this (and perhaps other) designs that could make a significant difference to our global energy consumption patterns.