Boise Air Terminal/Gowen Field traces its origins to April 6, 1926, when a gravel bed beside the Boise River, where Boise State University's campus stands today, became the city's first airport. On that same day, Varney Air Lines pilot Leon Cuddeback landed a Laird Swallow biplane carrying mail from Pasco, Washington, completing the first privately contracted airmail flight in U.S. history. Varney, headquartered in Boise, would eventually become part of United Airlines.

The airport's current site dates to 1936, when the city began acquiring land south of the original field. By 1938 it had the longest runway in the United States at 8,800 feet. The U.S. military developed Gowen Field along the airport's southern edge beginning in 1941, naming it for First Lieutenant Paul Gowen of Caldwell, Idaho, an Army pilot killed in a crash in Panama in 1938. During World War II, bomber crews trained at Gowen Field in B-17 Flying Fortresses and B-24 Liberators, and more than 6,000 servicemen were stationed there, among them actor Jimmy Stewart, who served as a flight instructor for roughly six months in 1943. The military returned the field to the city in 1946; the Idaho Air National Guard has leased the Gowen Field portion ever since and today operates the 124th Fighter Wing there.

BOI is the largest airport in Idaho and a focus city for Alaska Airlines, which runs the most flights from the airport. Seattle, Denver, Phoenix, Salt Lake City, and San Francisco rank among its busiest routes. A $108 million terminal expansion completed in 2003 unified the passenger facility, and the airport recorded more than 5.2 million passengers in 2025. In 2026 the airport marked its centennial while advancing a multi-year capital improvement program that includes a new concourse of up to 10 gates, a consolidated rental car facility, and expanded baggage claim, all aimed at keeping pace with one of the fastest-growing metro areas in the American West.