Seattle–Tacoma International Airport

Seattle-Tacoma International is the Pacific Northwest's dominant gateway and one of the fastest-growing major airports in the United States, handling 50.9M passengers (2024) across 151 destinations on 58 airlines. SEA has climbed the U.S. passenger rankings more aggressively than any peer over the last decade, driven by the Puget Sound region's tech-industry expansion (Amazon, Microsoft, Boeing) and by a doubling of Asia-facing international service since 2015. Alaska Airlines operates its largest hub at SEA with more than 350 daily departures — roughly 60% of the airport's seat capacity — feeding a oneworld-aligned network across the West Coast, Hawaii, Mexico, and new transcontinental routes following Alaska's 2024 acquisition of Hawaiian Airlines. Delta runs its only West Coast transpacific hub from SEA with nonstop service to Tokyo, Seoul, Shanghai, and seasonal Beijing, and the airport is a key station for British Airways, ANA, Singapore Airlines, and Emirates' fifth-freedom Dubai–Milan extension. Three parallel runways — 11,901 ft (3,627 m), 9,426 ft (2,873 m), and 8,500 ft (2,591 m) — handle simultaneous independent operations, completed after a decades-long third-runway battle finally resolved in 2008. SEA sits at 433 ft (132 m) elevation on a narrow strip of land between Puget Sound and Interstate 5, with a single integrated terminal whose constrained footprint has driven a major expansion program (the International Arrivals Facility opened in 2022 adding a new Concourse A with 20 gates) and a second-terminal proposal under environmental review. The Port of Seattle's long-term masterplan targets 70M annual passengers. SEA's geographic position as the closest major U.S. mainland airport to Asia by great-circle distance makes it a structural beneficiary of Pacific-rim air-traffic growth.