Flights through air space controlled by the Jacksonville, Fla., traffic center were delayed for about an hour Friday while radio and phone contact with pilots and other facilities was down.
All aircraft whose flight route took them into the Jacksonville Center's airspace were delayed on the ground at their departure airports, according to the controller's union.
The Jacksonville Center is the nation's seventh-busiest and handles major north-south air routes for traffic coming to and from Florida and the northeastern U.S.
The ground stop ordered by the Federal Aviation Administration ended at about 1:35 p.m. after roughly 50 minutes, a spokeswoman for the Jacksonville Aviation Authority told the Associated Press.
FAA officials did not immediately return a call for comment.