Scalability and Evolutionary Dynamics of Air Transportation Networks in the United States

With the growing demand for air transportation and the limited ability to increase capacity at key points in the air transportation system, there are concerns that, in the future, the system will not scale to meet demand. This situation will result in the generation and the propagation of delays throughout the system, impacting passengers’ quality of travel and more broadly the economy. There is therefore the need to investigate the mechanisms by which the air transportation system scaled to meet demand in the past and will do so in the future. In order to investigate limits to scale of current air transportation networks, theories of scale free and scalable networks were used. It was found that the U.S. air transportation network is not scalable at the airport level due to capacity constraints. However, the results of a case study analysis of multi-airport systems that led to the aggregation of these multiple airports into single nodes and the analysis of this network showed that the air transportation network was scalable at the regional level. In order to understand how the network evolves, an analysis of the scaling dynamics that influence the structure of the network was conducted. Initially the air transportation network scales according to airport level mechanisms –through the addition of capacity and the improvement of efficiencybut as infrastructure constraints are reached; higher level scaling mechanisms such as the emergence of secondary airports and the construction of new high capacity airports are triggered. These findings suggest that, given current and future limitations on the ability to add capacity at certain airports, regional level scaling mechanisms will be key to accommodating future needs for air transportation.