Seattle–Tacoma International Airport
Seattle–Tacoma International Airport is the primary international airport serving Seattle and its surrounding metropolitan area in the U.S. state of Washington. It is in the city of SeaTac, which was named after the airport's nickname Sea–Tac, approximately south of downtown Seattle and north-northeast of downtown Tacoma. The airport is the busiest in the Pacific Northwest region of North America and is owned by the Port of Seattle.
The entire airport covers an area of and has three parallel runways. It is the primary hub for Alaska Airlines, whose headquarters are near the airport. The airport is also a hub and international gateway for Delta Air Lines, which has expanded at the airport since 2011., 31 airlines operate at Sea–Tac, serving 91 domestic and 28 international destinations in North America, Oceania, Europe, the Middle East, and Asia.
Sea–Tac was developed in the 1940s to replace Boeing Field, which had been converted to military use during World War II. A site near Bow Lake was chosen in 1942 and construction began the following year with funding from the federal government, Port of Seattle, and the City of Tacoma. The airport opened on October 31, 1944. The first scheduled commercial flights from the airport began in September 1947 and the terminal was dedicated on July 9, 1949. Sea–Tac was expanded in 1961 to accommodate jetliners and added new concourses and satellite terminals by 1973. The main runway was extended several times and twinned in 1970; the third runway opened in 2008 following several decades of planning due to local opposition.
Several major concourse expansions and renovations were initiated in the 2010s to accommodate passenger growth at Sea–Tac, which had become a new hub for Delta Air Lines. A new international arrivals facility opened in 2022 as part of the program. In 2023, Sea–Tac served 50,887,260 passengers, 2% below the all-time record set in 2019.
In 2025, Seattle–Tacoma International Airport set an all-time record with 52,715,181 passengers served, slightly higher than the all-time record set in 2024.
History
Construction and early growth (1942–1967)
A shared public airport was proposed by the Port of Seattle and Port of Tacoma in the late 1920s, but deferred plans after the legality of public ports operating such facilities was rejected by the state attorney general in a published opinion. The state legislature authorized municipal corporations such as public ports to establish aviation facilities in 1941. The Port of Seattle accepted a $1 million grant from the Civil Aeronautics Administration in March 1942 to construct a new airport to serve the Seattle area after the U.S. military took control of Boeing Field during World War II. A site on U.S. Route 99 near Bow Lake south of Seattle was chosen at the end of the month ahead of another candidate near Lake Sammamish that was considered too close to the Cascade Range. The City of Tacoma provided $100,000 towards the airport's construction costs as part of a deal for the Bow Lake site, centered around an existing private airfield plagued by heavy fog. Construction of the airport, which was named Seattle–Tacoma in recognition of Tacoma's contribution, began with a groundbreaking ceremony on January 2, 1943.The project was originally estimated to cost $1.7 million, but the sandy soil conditions drove the final construction price to over $4.2 million. The airport's plateau was formed through of excavated earth. A proposal to rename the airport for Boeing president Philip G. Johnson shortly after his death in September 1944 was rejected by Port of Seattle commissioners due to the objections of Tacoma. The first ceremonial landing at Seattle–Tacoma Airport was made on October 31, 1944, by a United Air Lines DC-3 carrying local elected officials and civic leaders. The first commercial flights launched in May 1945 with Northwest Airlines, but use was limited due to the U.S. Army Air Force's need for the airport to stage Boeing B-29 bombers for delivery. Various airlines had irregular flights to the airport, which used a Quonset hut with limited heating as a terminal until a permanent building was financed by a bond issue that voters approved in 1946.
The first scheduled commercial flights began on September 1, 1947, with Northwest Airlines and Western Airlines operating ten daily departures. They were joined by United, Alaska, Trans-Canada, Western, and Pan Am by 1951 as airlines departed from Boeing Field. The terminal at the renamed Seattle–Tacoma International Airport was formally dedicated by Governor Arthur Langlie on July 9, 1949, in front of a crowd of 30,000 spectators. The building, designed by architect Herman A. Moldenhour, included a rooftop control tower and glass courting walls in the concourses. The airport originally had four runways at 45-degree angles, between long, for crosswind operations. The two perpendicular runways were arranged into an "X"-shape that intersected near the longest, north–south runway; an additional runway to the south ran east–west. The terminal building's "inverted V" shape was arranged to match the runway layout. The north–south runway was lengthened to in 1950, to in 1955, and to in 1958 to support commercial jetliners.
The first parking lot at Sea–Tac opened in 1955 with room for 527 vehicles. The United States Postal Service opened its air mail terminal at the airport in 1957 to serve areas west of the Mississippi River and mail bound for Asia; other government agencies, including the Weather Bureau and the Customs Service also established offices at Sea–Tac. On June 28, 1959, Japan Airlines became the first international carrier to operate at Sea–Tac when it began its service to Tokyo. Several projects were completed by 1961 to prepare for the Seattle World's Fair the following year, including a runway extension over South 188th Street, which was placed in an automobile tunnel that opened in July 1961. During construction of the runway extension in February 1961, the fossilized skeleton of a Megalonyx jeffersonii giant sloth was discovered and excavated for display at the Burke Museum in Seattle. The two-story North Concourse opened a month later with four gate positions to prepare for regular jetliner service; the concourse's wing was long and wide. Jetliner service began in October 1961 with Pan Am's Boeing 707 flights to Honolulu. The South Concourse opened in May 1961 alongside an expanded parking lot with capacity for 2,000 vehicles.
The long Concourse B opened in December 1964. It added eight gate positions, bringing the total to 19, a area housing international arrivals and the offices of U.S. Customs, Immigration, Public Health and the Department of Agriculture. Concourse C opened in July 1966. Four years later, it was extended to include another 10 gates, bringing the total to 35. The first non-stop flights from Sea–Tac to mainland Europe began in September 1966 with Scandinavian Airlines, who used a polar route to reach Copenhagen. A parallel second runway was completed west of the main runway in 1970.
Later expansions and third runway (1967–2008)
The Port embarked on a major expansion plan, designed by The Richardson Associates and lasting from 1967 to 1973, adding a second runway, a parking garage, two satellite terminals and other improvements. In 1973, $28 million new terminal was built over and around the 1949 structure; the new terminal quadrupled the area for public use. On July 1, 1973, the airport opened two new satellite terminals, along with an underground train system to connect them to the Main Terminal. These fully automatic shuttle trains were among the first of their kind in the United States. Also unprecedented in any U.S. airport: as part of the expansion the Port commissioned $300,000 worth of artworks; these were the start of what would become a large public art collection owned by the Port.In the mid-1980s, the Main Terminal was renovated and another was added to the north end. Concourse D was expanded in 1987 with a rotunda that added four new gates. In 1993, Concourses B, C, and D were renovated. The project, designed by NBBJ, included the addition of and the renovation of of space in Concourses B, C, and D. On June 15, 2004, the new Concourse A was unveiled with 14 new gates, a dozen new restaurants, new artwork and the airport's first moving sidewalks.
Residents of the surrounding area filed lawsuits against the Port in the early 1970s, complaining of noise, vibration, smoke, and other problems. The Port and the government of King County adopted the Sea–Tac Communities Plan in 1976 to address problems and guide future development. The Port spent more than $100 million over the next decade to buy homes and school buildings in the vicinity, and soundproof others nearby. In the mid-1980s, the airport participated in the airport noise-compatibility program initiated by Congress in 1979. Airport-noise contours were developed, real estate was purchased and some homes were retrofitted to achieve noise mitigation.
In 1978 the U.S. ended airline regulation, and the U.S. airlines were allowed to determine routes and fares without government approval. Deregulation resulted in some new service to Seattle, including from TWA, then the fourth-largest U.S. airline, as well as Delta, National, and American.
Image:SeaTacTerminalN.jpg|thumb|right|Alaska and United planes at the North Satellite Terminal in 2008
Image:View from SEA Tower.jpg|thumb|right|Sea–Tac Airport in September 2007 as runway 16R/34L was under construction
Shortly after the death of U.S. Senator Henry Martin "Scoop" Jackson, the Port Commission voted on September 13, 1983, to change the airport's name to the Henry M. Jackson International Airport. Citizens of Tacoma were angered by the removal of their city's name despite their contribution to the airport's original construction budget, which had come with a promise to share the name. An additional complicating factor was the existence of another Jackson International Airport in Jackson, Mississippi. During the November 1983 elections, an advisory referendum in Tacoma on the airport's name endorsed the original name by a 4–1 margin and two incumbent Port commissioners were defeated by candidates in favor of restoring the Sea–Tac name. Helen Jackson, the widow of the late senator, expressed her desire that their family remain neutral in the debate. With a 3–2 vote of the Port Commission on February 28, 1984, the name reverted to Seattle–Tacoma International Airport and the four signs with Jackson's name were removed.
In the late 1980s, the Port of Seattle and a council representing local county governments considered the future of air traffic in the region and predicted that the airport could reach capacity by 2000. The rising use of regional airliners such as Horizon Air caused aircraft movements to triple from 1978 to 1990 and air cargo use at the airport had also risen dramatically. In 1992, the planning committee concluded that the best solution was to add a third runway to the airport and construct a supplemental two-runway airport in one of the neighboring counties. Members of the community opposed a third runway, as did the Highline School District and the cities of Des Moines, Burien, Federal Way, Tukwila, and Normandy Park, but a 1994 study concluded there were no feasible sites for an additional airport. The Port of Seattle approved a plan for the new runway in 1996, prompting a lawsuit from opponents. The Port secured the necessary permits by agreeing to noise reduction programs and environmental protections. Runway opponents appealed these permits, but dropped their challenges in 2004.
The third runway, measuring long, opened on November 20, 2008, with a construction cost of $1.1 billion. Parallel to the existing two, the new runway is west of runway 34R, allowing landings on both in times of low visibility. The older runways are apart, too close to allow use of both in low visibility. The third runway project included of fill dirt and several retaining walls, the longest of which is long and tall.