The U.S. Federal Bureau of Investigation said Saturday that no bombs were found on two planes at Atlanta's main airport after authorities received what they determined to be credible bomb threats, posted on Twitter.
Authorities searched the planes with bomb-sniffing dogs.
A spokesman at Hartsfield-Jackson Atlanta International Airport said the threats appeared aimed at an incoming Delta Airlines flight from Portland, Oregon, and a Southwest Airlines flight from Milwaukee, Wisconsin.
Fighter jets had scrambled from a military base in South Carolina to escort both aircraft, which landed safely.
The airport is the world's busiest by passenger volume and the number of landings and takeoffs. It accommodated more than 90 million passengers in 2012.