Las Vegas McCarran International Airport’s air traffic control tower was temporarily closed when an air traffic controller tested positive for the coronavirus.
The FAA said it led to multiple cancellations and flight delays of several hours.
By late Thursday, Southwest Airlines cancelled more than 200 flights according to FlightAware.
There were nearly 500 flight cancellations in total.
The airport remained open despite the tower closure but at a much reduced capacity by using a backup system at the Las Vegas Terminal Radar Approach Control.
"The agency is working to determine how many air traffic controllers will have to self-isolate from being exposed to the controller who tested positive or areas the controller worked in," the FAA said.
Operations will ‘remain at a reduced rate until it is resolved’ the FAA added.
All passengers have been advised to check with their airline regarding possible delays or cancellations.
Earlier this week another control tower at Chicago Midway International Airport was forced to close after three ATC workers tested positive, causing delays and cancellations there.
