The effects of the events of Sept. 11, 2001 have had an unprecedented affect on the aviation industry. For example, in the six months after the events of 9/11, October 2001 through March 2002, total passenger traffic at PDX decreased 13.6 percent from the same period the year before. However, even before 9/11, the overall economy was having a negative effect on the industry. While it appears that economic conditions have stabilized somewhat, the industry as a whole remains relatively weak financially.

As a response to the events of 9/11 and the generally negative trends demonstrated by the aviation industry as a whole, the Port chose to switch to the Federal Aviation Administration-approved Low Aviation Demand Forecast as its basis for long-term master planning. The objective of forecasting is to estimate future levels of airport activity from which the demand for facilities can be derived. By comparing the demand for future facilities with existing facilities, it is possible to identify airport facility deficiencies.

In 1999, the Port hired P&D Aviation to develop growth forecasts through 2020 using a Federal Aviation Administration-approved methodology. The growth forecasts focused on three indicators: enplaned passengers, cargo and aircraft operations. The resulting work contained three projections for each of the indicators: Low, Base and High. The following figure is a comparison of the base and low 20-year forecasts.