Fig. 2.

Network evolution 2004–2019.

Note: Panels a) - c) depict the evolution of network size statistics (airports, links, and flights) in the EATN and its layer. Based on snapshots of the first calendar week in April and November each year. Panel d) depicts distributions of link weights ($w)$, airport degree (k), and airport strength ($s)$ based on April 2004 and 2019 for the EATN. Distributions for random network realizations with size statistics equal to empirical networks of April 2019 but with unpreserved degree sequence (Bernoulli-type) as a reference in grey. Panels e)-f) depict evolution in average quickest path length over time for EATN, layers and communities. The insets provide the ratio between the empirical networks and the median values source for random network realizations with preserved degree and strength sequence. Departure times remain thereby unchanged but arrival times at the ‘randomized’ destination nodes are adjusted according to the corresponding flight distance between the nodes.