The San Luis Obispo County Regional Airport (CSO) is a public airport located in San Luis Obispo County, California, United States. It is one of the busiest general aviation airports in the United States and serves as a gateway to Central California. The airport has three runways and is capable of handling large aircraft, including international flights. The airport is also used for air ambulance and air cargo services.

Opened in 1928, the San Luis Obispo County Regional Airport served as a training ground for pilots during World War II. The airport was used by the US Air Force during the Korean War and the Vietnam War. In 2007, the airport became a focus for local community leaders in their effort to turn CSO into an international airport. In 2009, a new passenger terminal opened at CSO, making it one of the largest airports in California with total passenger capacity of 3 million passengers per year.

In June 2010, American Airlines announced that it would begin service to Dallas/Fort Worth International Airport from CSO beginning in late 2011. This marked the first time an airline had served the airport since American Airlines ceased service to Los Angeles International Airport in 2001. In November 2010, Delta Airlines announced that it would also start serving CSO from Atlanta's Hartsfield-Jackson International Airport beginning in December 2011. Both airlines cited CSO's proximity to major markets as one of the reasons for their decisions to begin service at CSO.