Greenville-Spartanburg International Airport — Greenville/Greer/Spartanburg, United States

GSP is Greenville-Spartanburg International Airport, a significant regional hub in upstate South Carolina serving the Greenville, Greer, and Spartanburg metro area. Unlike many smaller entries with this code prefix, GSP handles substantial commercial traffic with multiple major U.S. airlines offering nonstop routes to hubs across the country. The airport sits near BMW's large manufacturing plant and other industrial employers, giving it a strong business travel component alongside leisure traffic. GSP has undergone terminal expansions over the years to accommodate growing passenger numbers in the fast-growing Upstate South Carolina region. It also supports general aviation and some cargo operations, making it a genuinely multi-purpose regional airport.