Revisiting competition and complementarity in multiple airport systems: An analysis of air routes and flights

Studies have contributed to airport competition issues in metropolitan areas; however, most have focused on passengers’ airport choices. Proposing a more systematic framework as well as a measuring method, this study contributes to the understanding of competition and complementarity in multiple airport systems (MASs). In this context, our research revisits MASs from the perspective of air routes and flights. These two approaches were combined. First, a quantitative analysis was conducted to investigate the degree of route overlap between airports belonging to the same MAS, ranging from strong complementarity to strong competition. In the second step, a qualitative analysis focused on the regulatory and policy context in which five MASs (Seoul, Brussels, Shanghai, Miami, and Montreal) were developed. This helps determine how much airports cooperate or compete with each other. Empirical evidence from 37 two-airport MASs worldwide suggests that inter-airport matches occur on less than 20% of routes that offer more than 40% of seats. Qualitative analysis confirmed a range of contexts, from genuine cooperation to forced regulation to de facto complementarity and head-on competition. Our findings broaden the understanding of MAS competition and complementarity profiles worldwide and their reasons.