O'Hare International Airport in Chicago was the busiest airport in the U.S. last year, surpassing Hartsfield-Jackson Atlanta International Airport for the first time in four years.
The Federal Aviation Administration released data on Monday showing that O'Hare had more than 903,000 arrivals and departures during 2018. Atlanta's airport was second, with more than 895,000 arrivals and departures.
Los Angeles International Airport, Dallas-Fort Worth International Airport and Denver International Airport round out the top five.
O'Hare last held the top spot in 2014.
Last year, O'Hare operations increased 4.2 percent, compared with a 1.8 percent increase in Atlanta. United Airlines is the largest carrier at O'Hare and has been adding more flights from its hub at the Chicago airport to smaller cities throughout the Midwest.