A study of the U.S. domestic air transportation network: temporal evolution of network topology and robustness from 2001 to 2016

The U.S. air transportation network (ATN) is critical to the mobility and the functioning of the United States. It is thus necessary to ensure that it is well-connected, efficient, robust, and secure. Despite extensive research on its topology, the temporal evolution of the network’s robustness remains largely unexplored. In the present paper, a methodology is proposed to identify long-term trends in the evolution of the network’s topology and robustness over time. The study of the U.S. domestic ATN’s robustness was performed based on annual flight data from 1996 to 2016 and network analytics were used to examine the effects of restructuring that followed the 9/11 events. Centrality measures were computed and a node deletion method was applied to assess the network’s tolerance to a targeted attack scenario. The outcome of this study indicated that the 9/11 terrorist attacks triggered vast restructuring of the network, in terms of efficiency and security. Air traffic expanded, as new airports and air routes were introduced, allowing the network to recover rapidly and become more efficient. Security concerns resulted in significant improvement of the network’s robustness. Since 2001, the global traffic and topological properties of the U.S. ATN have displayed continuous growth, due to the network’s expansion. On the other hand, the results suggest that although the system’s ability to sustain its operational level under extreme circumstances has lately improved, its tolerance to targeted attacks has deteriorated. The presented methodology has shown its potential to be applied on different network levels or different transportation networks, in order to provide a general perspective of the system’s vulnerabilities.