The authors sought to establish that airports do not have" catchment areas" as such and that air travelers make choices among avaUable airports when they elect to travel. A mode) that describes this choice mechanism will permJt airport syste. ms to be planned on a more reliable basis. This work develops a model for p~ ngers In central England based on data collected in 1975 and 1978 by the Civil Aviation Authority. The model chosen was one or discrete behavioral choice; the particular form that was successrully caJJbrated was Ole muJtlnomlal logtt model. For business and Inclusive tour travel, the most Important variables of choice were a. ccess time to the airport and (requency to the chosen destination. For domestic and leisure trips there were three factors: air fare, access time, and frequency or available Oights, in that order of importance. The calibrated model showed high agreem. ent between observed and predicted market shares. The model was also found to be transferable to data from a separate survey of air travel from the London area. The model is expected to be of· use to airport authorities and airlines ln planning and determining business strategy in the lncreaslngJy competitive deregulated environment or air transport.

It is not unusual for aiiports to be discussed in terms of" catchment areas," as if an individual airport served a particular area of a country. The concept of catchment would, perhaps, be valid if all air trips originating in a particular area invariably used the same airport, hit this is not so. De Neufville (1) quite rightly pointed out the error of using this term in conjunction with airports because in many situations people can and do choose the airport they will use. Air trips are not invariably drawn to a single airport. If he has a choice of airport, the passenger is likely to choose on the basis of the perceived overall level of service he obtains from his selection. In a small country like the United Kingdom where there are many commercial service ailports it is not possible to adhere to the belief in nonoverlapping airport catchment areas. Little research has, however, been carried out to obtain a better understanding of how trip makers choose among the services offered by competing ailports. This is partly because carrying out research on airport selection is likely to involve time-consuming and costly passenger surveys.