An air traffic computer issue led to a nationwide ground stop for flights to and from Florida.
It is unclear what caused the equipment outage.
The ground stop led to delays after thousands of flights were already cancelled over the Christmas holiday weekend amid a Polar Vortex.
Travelers desperate to get home were hit with more delays on Monday.
All airliners were affected.
NBC Miami reported:
Flights to and from Florida airports were experiencing delays after a radar issue caused a ground stop Monday, officials said.
Federal Aviation Administration officials said the volume of traffic into Florida airspace was slowed following an air traffic computer issue.
Officials at Miami International Airport said there was a nationwide ground stop to and from Florida due to a radar link outage.
The issue was resolved and planes were slowly being allowed to depart, MIA officials said.
American Airlines tweeted at the issue originated at the MIA control center and was affecting all carriers.
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