Hartsfield-Jackson Atlanta International Airport (ATL) is the primary hub for Delta Air Lines, which accounts for nearly 75% of the airport's traffic. However, as the world's busiest airport, it hosts almost every major domestic and international carrier. Major U.S. airlines include Southwest (which maintains a large secondary hub here), American, United, JetBlue, Spirit, and Frontier. On the international side (Terminal F), you will find the giants of the SkyTeam alliance such as Air France, KLM, Korean Air, and Virgin Atlantic, alongside other global leaders like British Airways, Lufthansa, Qatar Airways, Turkish Airlines, and Ethiopian Airlines. In 2026, the airport has also seen an expansion of low-cost international service from carriers like Avelo and Breeze, as well as increased cargo operations from FedEx and UPS, reinforcing its status as the most connected node in the global aviation network.