Tri-Cities Airport (originally Pasco Airport) is a public airport in the northwest United States in Franklin County, Washington. Located northwest of Pasco, it serves the Tri-Cities metropolitan area in southeast Washington, and is the third largest commercial airport in the state. The facility has three runways and covers . History The Tri-Cities Airport (originally Pasco Airport) was the site of the first airmail contract flight between Elko, Nevada, and Pasco, Washington, made by Varney Airlines, (later United Airlines) in 1926. The airport was relocated to its present site and became known as the Franklin County Airport; the U.S. Navy built Naval Air Station Pasco during World War II. After the war, the Navy sold the field to the city of Pasco, but retained training privileges. Several Navy aircraft, especially the P-3 Orion, used the field for landing and take-off training. The Port of Pasco then took ownership in 1963 and opened doors to a new terminal building in 1966. In 1955, the old administration building became the home of the newly established Columbia Basin College, which it remained until the current facility near Interstate 182 was built in 1966. The building later was leased to the Pasco School District #1, for use as Pasco Alternative High School (now New Horizons High School) until it was destroyed by fire in the mid-1980s. The new school is now sited near Columbia Basin College. Pasco has had jet flights on several airlines, including Air West/Hughes Airwest with Douglas DC-9s, Cascade Airways with BAC One-Elevens, Delta Air Lines with Boeing 727-200s and 737-300s, Western Airlines with Boeing 727-200s, 737-200s, and 737-300s, Frontier Airlines with 737-200s, Pacific Southwest Airlines (PSA) with BAe 146-200s, Alaska Airlines with Boeing 727s, Horizon Air with Fokker F-28s, and West Coast Airlines with DC-9s. Currently, scheduled passenger flights are mostly regional jet and turboprop, although Allegiant Air operates Airbus A319s/320s, Delta operates Airbus A319s/320s and Boeing 717s, and Avelo operates Boeing 737s. Horizon Air, a subsidiary of Alaska Airlines, currently uses a mix of Bombardier Q400 turboprop aircraft, and E-175 jets at Tri-Cities, but has announced plans to transition to all E-175 jets by the end of 2023. An expansion and remodel project took place in 1986 that included access roads, parking lots, aircraft parking apron and more than doubling the size of the terminal. In 2003, the airport underwent another expansion and remodel that added an additional to the