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 in 1942 and was the third-busiest Naval training base in the United States during World War II. After the war, the Navy transferred the field to the City of Pasco for one dollar, but retained training privileges. Several Navy aircraft, especially the P-3 Orion and the P-8 Poseidon, used the field for landing and take-off training. The Port of Pasco 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 situated 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 and Delta operates Airbus A319s/320s and Boeing 717s. Horizon Air, a subsidiary of Alaska Airlines, formerly used a mix of Bombardier Q400 turboprop aircraft and Embraer E175 jets at Tri-Cities but now uses E175 jets exclusively since 2023. An expansion and remodel project took place in 1986 which 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 3,000 square feet (280 m2) to the ticket lobby and boarding area. In 2014, the Port of Pasco approved a $42 million renovation and expansion, planning to double the size of the terminal. The construction began in August 2014 and finished in January 2017. The first phase of the expansion was completed on September 7, 2015, which included a new west concourse with Gates 3, 4 and 5 as well as new car rental and baggage claim areas. The second phase started shortly thereafter, planning to demolish the old boarding area and replace it with a new east concourse to house Gates 1 and 2. On January 27, 2017, the $42 million airport renovation and expansion, which added a new terminal, security area and baggage handling system was officially opened to the public. The new terminal is intended to meet the needs of the Tri-Cities metropolitan area for the next 20 years, with passenger enplanements/deplanements in 2019 reaching a new high of 870,900. The airport received a $7 million grant in 2025 to help fund the project.