Flights at Hartsfield-Jackson International Airport are being delayed due to thunderstorms and wind, amid severe weather in the area.
Atlanta-based Delta Air Lines said it had diverted about 50 flights.
"We are working to safely return the diverted flights to Atlanta and re-accommodate customers on alternate flights," Delta said in a written statement.
The Federal Aviation Administration's website on air traffic delays says some departures are being delayed from Atlanta.
Flights due to arrive in Atlanta were being delayed 46 minutes to an hour and increasing, according to the FAA updates.
By mid-afternoon, the Atlanta airport had two flight cancellations, after seven flight cancellations due to weather on Saturday, according to spokesman Reese McCranie.
Travelers with flights scheduled for Sunday should check their flight status with their airline.
Meanwhile, Chicago-based United Airlines said Sunday evening it has grounded all of its domestic flights due to a technological glitch. That includes four United flights from Atlanta that are grounded, according to Hartsfield-Jackson. "We're working on a resolution. We apologize for the inconvenience," United said on its Twitter account.