TagForecast(43)

A draft working document prepared by the Commercial Aviation Work Group presents an unconstrained air travel demand forecast for Washington State's 17 busiest commercial airports, with Seattle-Tacoma International Airport (SEA) leading at approximately 26.3 million enplanements in 2025 out of a statewide total of nearly 29.8 million. The report, dated April 28, 2026, covers market analysis and air traffic forecasts across airports ranging from large hubs like Sea-Tac and Spokane International to smaller facilities such as Renton Municipal and Roche Harbor. The forecast is described as 'unconstrained,' meaning it projects potential demand without accounting for limitations in airport capacity or infrastructure.

This draft report, prepared by the Commercial Aviation Work Group and consulting firm Steer, presents an unconstrained air travel demand forecast for Washington State's 17 busiest commercial airports, with Seattle-Tacoma International (SEA) accounting for the vast majority of the state's approximately 29.8 million enplaned passengers in 2025. The forecast combines a short-term bottom-up model based on airline schedules with a long-term top-down model driven by macroeconomic factors such as GDP, population, and airfares, ultimately producing airport-level traffic projections. While focused on statewide aviation demand planning, the findings have direct relevance to Sea-Tac noise policy discussions given SEA's dominant share of regional air traffic.

This presentation, delivered on February 25, 2026, introduces the fundamentals of aviation forecasting as part of the airport planning process. It outlines how planners forecast passenger demand, aircraft operations, and automobile traffic, then identify physical, operational, and level-of-service constraints before developing and evaluating alternatives. The material emphasizes that while predicting future demand is inherently uncertain, structured forecasting is a critical first step in guiding airport infrastructure decisions.