Government data released Thursday shows that Hartsfield-Jackson Atlanta International Airport logged more than 976,307 flights in 2006. That's down .4 percent.
The Federal Aviation Administration says O'Hare was second busiest, with more than 958,643 flights in 2006. The FAA says that number was down 1.4 percent.
O'Hare spokeswoman Wendy Abrams says officials in Chicago aren't surprised that the Atlanta airport had more flights in 2006. She says O'Hare's flight restrictions have put a limit on takeoffs and landings.
A massive expansion plan for O'Hare is expected to be finished in 2013.