Application of a Defender-Attacker-Defender Model to the U.S. Air Transportation Network

Modeling, assessing and improving infrastructural resilience has been of increasing importance to national security in recent years. The U.S. air transportation sector, spanning approximately 500 airports and heliports, and hundreds of thousands of routes is of notable significance among transportation modes. This paper develops and solves a tri-level defender-attacker-defender optimization model to plan the optimal defense and operation of the US air transportation network against an intelligent attack. The tri-level aspect of the program refers to the defender first using available defensive assets to secure the system's connections, the attacker next using available offensive assets to attack unsecured connections, and finally, the defender guiding system operation to minimize operational cost. Different disruption and defense scenarios are explored, as well as the resulting passenger rerouting operations in the aftermath of each disruption. Results show that through the application of an optimal configuration combining route protection and flight rerouting, the effects of worst-case attacks on the network can be largely mitigated.