Hartsfield-Jackson Atlanta International Airport (ATL) is the primary global hub for Delta Air Lines, which accounts for nearly 75% of the airport's traffic. However, as the world's busiest airport, it hosts a vast array of domestic and international carriers. Major U.S. airlines include Southwest Airlines (the second largest carrier at ATL), American Airlines, United, JetBlue, Spirit, Frontier, and Alaska Airlines. Internationally, ATL is served by many members of the SkyTeam alliance due to their partnership with Delta, such as Air France, KLM, Korean Air, Virgin Atlantic, and Aeromexico. Other major international players include British Airways, Lufthansa, Turkish Airlines, Qatar Airways, and Copa Airlines. The airport is designed with seven parallel concourses (T, A, B, C, D, E, and F), with Concourse F serving as the dedicated international terminal where most foreign flag carriers are stationed.