摘要: |
Honolulu International Airport is one of the dozen busiest airports in the United States. It provides a port of entry for foreign flights and both domestic and interisland terminals. For Hawaii's airport engineers and planners, this status makes short- to medium-term air travel forecasts essential, particularly for landside applications. A unique model system is described with separate models for each origin region or country. The models are estimated with the Cochrane-Orcutt regression procedure. Major explanatory variables include the gross national product (GNP), gross domestic product (GDP) (in various forms), and the consumer price index (CPI). Exchange rates, strength of currencies, and variables for wars, recessions, and airline strikes are also introduced. The models adhere closely to the actual number of arrivals, and all variables perform as expected. The USA model has an overall error rate (for the 18 years of the estimation span) of less than 0.05% and annual extreme errors ranging from -6.4% to 5.7%. The Japan model also has an overall error rate of less than 0.05% and annual extreme errors ranging from -7.5% to 10.4%. Near-future values for explanatory variables can be obtained from major economic organizations, thus the use of the model system requires only that planners update variable values annually from regularly issued publications. Long-term forecasts are more difficult due to the lack of published data. In those cases, the user must resort to a combination of trend extrapolation with ARIMA, as shown in this discussion, and educated estimates based on contemporary macroeconomic literature. |