Air Transportation and United States Urban Distribution

THE dynamic role of transportation in the regional development of the United States is well known and well studied.' Canals, railroads, and highways, channeling the flow of traffic, have created urban alignments, hinterlands, and nodal points. Now air transportation promises. to become a vital factor. Geography, with its emphasis on spatial relations, represents a particularly effective approach to an analytical consideration of this rapidly growing form of transportation and its possible regional implications.' In its present stage of development United States air transportation is concentrated on the mediumand long-haul carriage of passengers between cities. Its ultimate impact on the urban pattern depends on the relative technological advance of air and surface transport in terms of both freight and passenger traffic. However, even in the present, passenger-oriented stage it is possible to note certain significant relationships between the distribution of United States cities and that of air-passenger traffic. This paper is an attempt to ascertain some of these relationships from the empirical evidence presented on a series of maps. In particular, the effects on air traffic of such urban characteristics as size, function, proximity of other cities, and railroad services will be considered. The method used is (i) comparison of airpassenger and urban-population maps to determine the urban features of most significance in air-passenger traffic; (2) more detailed analysis of a map of per capita traffic-generation indexes in terms of these features.