Distance, intervening opportunities, city hierarchy and air travel

Summary and ConclusionsThis study examines the influence of the spatial structure of city locations on air travel by considering the factors of intervening opportunities and the hierarchical system of cities in addition to the simple dimension of distance. The statistical results show that the familiar strength of the gravity model is matched by that of the intervening opportunities model, but only when all cities are analyzed together. The disaggregation of cities by size and region (hierarchy) leads to a spotty performance by both models. The generality of the gravity and intervening opportunities models is thus called into question, and the potency of the hierarchical city organization as a contributing influence determining air traffic flows is demonstrated.