The study covers various aspects of the nation's air transportation system and takes into account the possible benefits of introducing a new class of small, lightweight jets that could share the load now handled by commercial airliners, reducing congestion at major airports. Companies using these jets are forming air taxi services that could be based at the nation's thousands of small airports to ferry passengers between cities.

"There have been other studies of next-generation air transportation systems, but they typically focus on particular aspects or details, such as the need for a certain kind of airplane, radar system or runway additions at large airports," DeLaurentis said. "What we do in this study is look at technological, economic and policy factors simultaneously, and that was our unique starting point."

A report based on the research was completed earlier this year and submitted to NASA, the sponsoring agency. Report findings include recommended policy changes, as opposed to concentrating exclusively on upgrading technologies.

The researchers took a first-of-its-kind "system of systems" approach, or a method of analyzing a complex system that is made up of many component systems, to study airport issues, DeLaurentis said.

An interdisciplinary team of faculty members and students in civil engineering, aerospace and computer science created the simulation, said DeLaurentis, who led the research. The researchers combined two new mathematical techniques called agent-based modeling and network theory to integrate all of the components within the air transportation system and predict overall performance. The model mimics the behavior of service providers, such as the major airlines and small air taxi companies, along with the infrastructure providers, such as the Federal Aviation Administration and U.S. Department of Transportation.

"You can almost think of it as a video game where the service providers are adding flights and subtracting flights and doing the best they can to satisfy changing demand, and the FAA is trying to catch up and add the capacity necessary to meet the needs of the airlines," DeLaurentis said. "One of the findings was that if the infrastructure providers were not able to keep pace with demand, the service providers would stagnate. They would be unable to add the flights that they needed. Yet, such agility or responsiveness is critical.

"Improving agility, we found, requires not so much that you build a brand new runway at every large airport. You need to be able to add capacity in a variety of other quicker ways. One of the problems in the current system is that it takes so long to develop new capacity at a major airport that by the time the capacity is available, the demand has already changed."