Harry Reid International Airport (IATA: LAS, ICAO: KLAS, FAA LID: LAS), until 2021 called McCarran International Airport, is the main gateway for international and domestic flights to the Las Vegas Valley, Nevada. It is located five miles (8 km; 4 nmi) south of downtown Las Vegas, in the unincorporated area of Paradise, and covers 2,800 acres (4.4 sq mi; 11.3 km²) of land.

Clark County Commission owns the facility and its Department of Aviation oversees airport operations.

In December 2021, the Clark County Commission renamed the airport to honor former U.S. Senator Harry Reid of Nevada. The airport comprises four runways and three passenger terminals encompassing five concourses, which are linked by an automated people mover system. Alongside Reno–Tahoe International Airport, Reid is one of only two U.S. airports that offer slot machines within its terminal buildings.

The airport opened in January 1943 as Alamo Field and initially catered to general aviation. In December 1948, it was rechristened for U.S. senator Pat McCarran, and commercial airlines shifted to it from the Las Vegas Army Airfield. Passenger counts increased in the 1950s as the Strip expanded, leading to the construction of a new terminal. McCarran later came to be seen as the model for the common-use approach to airport resources in the United States and pioneered radio-frequency identification of baggage. Terminal 3 was added in 2012, and the airport was renamed in honor of Senator Reid in 2021.

Reid is served by over 30 airlines and is an operating base for Allegiant Air, Frontier Airlines, JSX, Southwest Airlines, and Spirit Airlines. Southwest became its dominant carrier in the 1990s. In 2024, over 58.4 million passengers passed through the airport, the most in its history. Reid has international flights to cities in Asia, Europe, and North America.

George Crockett, a flight instructor, built Alamo Field in 1942 on the site currently occupied by Harry Reid Airport. Crockett named it in honor of his forefather Davy Crockett, who had fought in the Battle of the Alamo. The airfield opened in January 1943. It catered to general aviation and included three gravel runways, a flight school, and a terminal building. Meanwhile, all commercial airlines flew into the Las Vegas Army Airfield. They shared the facility with the Army Air Forces, which had been operating an air base there since the attack on Pearl Harbor. The base closed in 1946.

With the onset of the Cold War, the military said it was amenable to reopening the base, but it wanted the airlines to move elsewhere. Crockett was willing to let them use his airfield, so the Clark County Commission entered into negotiations with him. In the meantime, the county held a bond election to fund construction work that would enable Alamo Field to handle commercial operations. Proponents of the bond issue, who included the chamber of commerce and casino executives, sought the economic benefits of both an air base and a modern airport capable of serving the increasing numbers of tourists that they expected to arrive. Voters approved the bond in 1947. With the help of U.S. senator Pat McCarran of Nevada, the county finalized a deal with Crockett to purchase his airfield the following year. On December 19, 1948, the airport was renamed McCarran Field and began receiving passenger flights.

The growth of the Las Vegas casino industry during the 1950s fueled a rise in air traffic; the city went from receiving 36,000 passengers in 1948 to nearly one million in 1959. In September 1960, United Airlines became the first carrier to offer jet flights to Las Vegas. The airport was ill-equipped to handle the increasing passenger counts and the advent of commercial jetliners. Consequently, the county built a new terminal, which opened in March 1963. Another expansion project, which included adding Concourses A and B and lengthening the runways, ended in 1974. However, traffic levels had already rendered the project insufficient by the time it was completed. Airport officials therefore prepared for further expansion.