Hartsfield-Jackson Atlanta International Airport (ATL) has long been recognized as the busiest airport in the United States, based on passenger traffic. Located just south of downtown Atlanta, it has grown from a regional airport into a sprawling, efficient hub that connects millions of passengers annually to destinations worldwide, making it a crucial transportation asset in North America.

Defining the Busiest Airport

While passenger traffic remains the widely accepted metric for measuring airport activity globally, other airports, such as Chicago O’Hare International Airport (ORD), have used alternative metrics like aircraft movements to make their case for the busiest airport. However, this has sparked a debate on how airport activity should be measured, highlighting the complexity of defining the busiest airport.

Passenger Traffic Benchmark

In 2025, Hartsfield-Jackson Atlanta International Airport handled approximately 106. 3 million passengers, solidifying its position as the busiest airport in the US and the world. As the most comprehensive indicator, passenger traffic reflects the number of people traveling through the airport, including local demand and transit passengers. Atlanta’s mega hub structure allows it to concentrate a large number of passengers at one location, contributing to its high passenger volume. In comparison, Chicago O’Hare International Airport handled 25 million fewer passengers in the same year, emphasizing Atlanta’s dominance in passenger traffic.

A New Debate on the Busiest Airport

In early 2026, a renewed debate arose over the busiest airport in the US, with Chicago officials using aircraft movements as a metric to argue their case. According to the US Federal Aviation Administration (FAA), Chicago O’Hare International Airport recorded 857,392 movements, surpassing Hartsfield-Jackson Atlanta International Airport, which recorded 807,625 movements. While aircraft movements provide insight into operational activity, Atlanta officials argued that passenger traffic remains the globally accepted standard for ranking airports and reflects the airport’s impact better.

The Power of a Mega Hub

Hartsfield-Jackson Atlanta International Airport’s dominance in passenger traffic can be attributed to its role as a major connecting hub, mainly for Delta Air Lines. As the airline’s largest and most significant base of operations, Atlanta serves as a central node, allowing the airline to efficiently connect passengers from various origins to their final destinations. Delta Air Lines holds a 79. 9% market share at the airport, followed by Frontier Airlines and Southwest Airlines, with 5. 3% and 4. 6%, respectively. The hub-and-spoke model used at Atlanta maximizes connectivity, and its extensive schedule ensures frequent and convenient connections, further enhancing the airport’s appeal as a transfer point.

The Busiest Domestic Routes

The busiest domestic routes from Hartsfield-Jackson Atlanta International Airport in 2025 were Orlando (MCO), New York LaGuardia (LGA), Fort Lauderdale (FLL), Tampa (TPA), Los Angeles (LAX), Dallas/Fort Worth (DFW), Miami (MIA), Newark (EWR), Denver (