Flight delay propagation in the multiplex network system of airline networks

The flight delay propagation and recovery processes in airline networks differ due to differences in airline network structures, capacity distributions, and base airport locations. When each airline network is regarded as a network layer, flight delay propagation and interaction in a multiplex network system (MNS) composed of multiple airlines will become more complex and variable. In this paper, flight delays from different airlines are considered propagation sources, and an MNSbased flight delay propagation model is established under the framework of the susceptible- infected-susceptible model. By comparing the independent propagation process of delays in a single-layer airline network and the interactive propagation process of delays in an MNS, we investigate the impact of network structure on flight delays to propose corresponding delay control strategies for different airlines. The results show that unlike in single-layer networks, in an MNS, the behavior of airlines at an airport facilitates or inhibits delay propagation in other layers by influencing the network characteristics and propagation rate. The same airport may even play different roles in different layers, depending on the function it has. Therefore, not all flights are infected or have aggravated delays when accessing the MNS; instead, they are impacted by combined factors such as on-time performance, network structure, and flight interaction.