WASHINGTON, United States (AFP) – American Airlines resumed flights Tuesday after a technical issue forced the world’s largest carrier to ground all its US flights for an hour during the busy year-end travel period, officials said.

“American Airlines reported a technical issue this morning and requested a nationwide ground stop. The ground stop has now been lifted,” Bridgett Frey, assistant administrator for communications at the Federal Aviation Administration, said in a statement.

The flight halt between 1150 GMT and 1250 GMT came on Christmas Eve, a day of exceedingly heavy air travel in the United States and elsewhere.

The FAA and American Airlines had yet to describe the nature of the technical issue and why it led to a nationwide ground halt.

Social media lit up with travelers complaining about how the delay might impact their holidays or ruin their rendezvous with family.

“Heck of (a) way to start Christmas,” tweeted one traveler who said the aircraft he was on returned to the gate and deplaned.

American posted replies to several travelers, urging patience and saying “Our team is working to get everyone safely in the air soon.”