On the topology of air navigation route systems

Air traffic management is the dynamic, integrated management of traffic in airspace. As aircraft fly through the sky, they follow pre-planned routes, much like highways on the ground. In this research, for the first time, the air navigation route (ANR) systems of 15 different countries from a consistent worldwide airspace database were analysed and, using complex network theory, these airspace structures were compared. The following five metrics were investigated: degree of a node, distance strength, weighted betweenness centrality, weighted closeness centrality and edge length distribution. For each metric, regression analysis was performed in order to identify abstract complex network patterns for each of the countries. It was found that the ANR networks for all 15 countries are rather heterogeneous. Furthermore, the degree distribution for all countries is better fitted by tetration, instead of an exponential function, as believed in previous analyses of single countries. An analysis of weighted betweenness centrality showed that some countries (e.g. the USA) are robust against random or targeted node failures while other countries (e.g. South Africa) are rather vulnerable. Hierarchical clustering based on regression coefficients shows that countries with similar geographical features are clustered together.