Greenville-Spartanburg International Airport

Halfway between Greenville and Spartanburg, the two largest cities in South Carolina's Upstate, lies Greer, where Greenville-Spartanburg International Airport is located. With more than 2.56 million passengers in 2023, the airport ranks third in traffic in South Carolina, behind only Myrtle Beach International Airport and Charleston International Airport. It is classified as a small-hub major commercial service facility by the Federal Aviation Administration (FAA) in the National Plan of Integrated Airport Systems for 2017–2021. Six major airlines provide 100 daily flights to 19 U.S. destinations and one-stop connections to hundreds of places worldwide, serving over 2.3 million people annually. The airport is a hub for air freight, which includes commodities and auto parts that are often transported around the US, to and from Europe, and to Mexico.

The cities vying for airline service had their own airports prior to the establishment of the Greenville–Spartanburg International Airport (GSP). Upstate corporate titans collaborated to secure a common airport for the two cities in the mid-1950s, spearheaded by Roger Milliken, an entrepreneur, businessman, and textile heir who served as CEO of Milliken & Company. A 1958 plan to build an airport connecting the two cities was brought before the legislative delegation representing the two counties, who authorized the project and appointed Milliken to lead the airport committee. When Greenville Downtown Airport closed on October 15, 1962, GSP took its place as the area's main airport for flights. GSP built new cargo and terminal facilities in the 1980s, and in the 1990s, the runway underwent two lengthening. The airport received Milliken's name in 2004. Since GSP is the nation's fastest-growing small airport, it was recognized with an ANNIE Award in 2011 by Airline and Airport News & Analysis.

With one runway, the airport is 3,500 acres in size. With a little area in Greenville County, the airport is primarily located in Spartanburg County. It's close to unincorporated areas and parts of Greer. Concourse A has gates A1–A9, and Concourse B, which has gates B1–B4, comprise the airport's single terminal structure. Every traveler has the same level of check-in. Through immigration and customs checks, the airport can process up to 250 people each hour. FedEx operates a sizable package facility at the north end of the airport. Three miles east, BMW has a facility facilitating the simple transfer of incoming parts to the company's production facilities.