Correlation between different network measures and passenger volume for the 50 airports considered in this study.

Measures (such as PR_C or BC_D) that take the flight route distance into account perform worse than the unweighted ones (PR or BC) or those weighted by the number of airlines serving the route (PR_A or BC_F), suggesting insensitivity to distance in air travelling. Refer to Table 3 for the description of the network measures.