A new report states that after taking into account the expansion of SEA and PAE, “some 27 million passengers in the region still require accommodation each year”.
SEATTLE — New state projections show the Puget Sound region will handle about 27 million more annual passengers than its commercial airports’ long-term capacity by 2050, with planners acknowledging that currently planned expansions alone will not close the gap. Where these travelers will go remains an open question.
The Washington State Department of Transportation’s (WSDOT) updated Washington Air System Plan projects that unrestricted passenger demand in the Puget Sound region will reach approximately 107 million passengers per year by 2050.
Even with planned expansion projects at Seattle-Tacoma International Airport (SEA) and Paine Field Airport (PAE), the two airports are expected to handle approximately 67 million passengers annually.
After taking into account travelers who may have diverted elsewhere, the report still determined that “approximately 27 million travelers each year still require accommodation in the region.”
Analysts note that these forecasts are based on Western Washington’s general economic growth in recent years, and of course, no one can predict what the future will hold.
SEA remains the center of the region’s aviation system and is implementing a major expansion plan that includes a second terminal with 19 gates, road improvements and new cargo facilities.
The FAA has completed the federal review process for the growth strategy and its accompanying state agencies may complete it by the end of 2026, a spokesman said.
SEA will serve 52.7 million passengers by 2025, and state planners say it is running out of space.
WASP found that SEA’s future terminal construction will still result in approximately 6 million fewer passengers than projected demand in 2041. The report said the airport “will have difficulty moving beyond current plans” given its layout and location.
“[SEA] SeaPort Airlines CEO Kent Craford told KING 5. “Everything needs to go smoothly for the machine to keep running.”
This makes the Paine Field a major relief valve in the region.
Paine Field’s long-term plan envisions increasing annual passenger handling to 4 million passengers by 2040, expanding terminal space and adding up to 15 additional gates. But WASP said the airport may eventually need to absorb much more traffic than currently planned.
Snohomish County recently finalized this expansion strategy and is actively working to implement elements of it, a spokesperson said. However, the terminal’s operator and owner, Propeller Airports, can progress construction work in its own time.
The WSDOT report found that if excess SEA demand shifts north, Paine Field’s annual passenger demand could increase to 6.7 million passengers, requiring a terminal “63 percent larger than the airport’s final planned terminal size.”
A spokesman attributed any differences in the two data projections to the recency of the WSDOT report.
Boeing Field officials, meanwhile, say the airport is too small and constrained by surrounding development to absorb major commercial growth.
“We are certainly unable to absorb the growth in passenger numbers projected by national aviation planners in the coming years,” airport officials said in a statement.
Instead, Boeing Field is expected to continue focusing on small commuter airlines, cargo operations and private aviation.
This leaves few obvious options for long-term growth in the region’s aviation industry.
A commercial aviation task force established by the Legislature is expected to release recommendations later this year on how Washington should meet growing demand for capacity.
“The long-term gap beyond 2040 is really something that the CAWG is trying to address right now,” CAWG Chairman Evan Nordby told KING 5.
But industry leaders say the private market may eventually adapt faster than the state can build infrastructure.
Crafford said Alaska Airlines may increasingly shift connecting flights to Portland instead of Seattle. Alaska CEO Ben Minicucci described Portland International Airport as a “pressure relief valve” for Seattle’s congestion problems in 2025.
“Airlines will be very proactive in resolving these issues themselves,” Crafford continued.
One potential solution does not appear in any document: the possibility of building an entirely new airport.
“To accomplish something as ambitious as building a new airport would require a complete shakeup of state government leadership,” Crawford concluded. “The airport we have is the airport we will have for the rest of our lives.”
