Network Characteristics of Air Traffic in the Continental United States

Air traffic is undergoing big changes both in developed and developing countries. The demand for air traffic in the United States is expected to grow to 2 or 3 times the current levels of traffic in the next few decades. This paper models demand for air traffic as a network with several thousand nodes. Recently, methods have been developed to study the network characteristics of large complex systems in many natural and engineering fields. Several networks exhibit the “scale-free” property that as the network grows in size, a small number of components have a disproportionate influence on the successful operation of the network. This paper describes the network properties of the current air traffic system and uses future scenarios of air traffic growth to understand the performance of future air traffic networks. The air traffic network exhibits an exponentially truncated scale-free behavior. It is shown that a three-times growth in the overall traffic may result in a ten-times impact on the density of traffic in certain parts of the United States. Thus, in addition to bottlenecks at major airports, the risk of en route traffic saturation calls for route restructuring and the introduction of new operational concepts, such as automation to increase en route capacity.