Weather 
Southwest Airlines flights were temporarily grounded Friday after a widespread computer outage knocked out the “IT backbone” for a number of major airlines – causing havoc for some fliers.
The system failure caused huge lines at airports served by Southwest and, according to outage-tracking website Downdetector, left some passengers unable to check in.
Customers also reported issues using Southwest’s app as the disruption threw a wrench into travel plans.
Southwest, the nation’s fourth-biggest airline, confirmed to The Post there was a brief interruption to its IT vendor, Amadeus, saying it had to check bags and board passengers the old-fashioned way during the temporary tech glitch.
Amadeus operates the back-end computer systems that power airline bookings, check-in, boarding and baggage handling.
Temporary outages were reported in California, Florida, Maryland, Ohio, Tennessee and Utah, where long lines and angry passengers were seen at airports.
Flyers sounded off on social media about being stuck at airport terminals, unable to board airplanes or pay for baggage online.
“Southwest Gate staff announcing system wide outage and all planes not in the air are stopped across the country,” claimed a passenger in Denver.
The problems began shortly after 8 a.m. ET, with frustrated travelers reporting they were “sitting in the terminal waiting on their computer system to hopefully come back to life.”
The snafu seemed to peak around 8:50 a.m., with Downdetector reporting that the technical difficulties began to ease – though travel issues reportedly lingered for some customers for more than an hour after the outage began.
“We apologize to our Customers for any inconvenience and hope to get them to their destinations as quickly as possible. Nothing is more important to Southwest than the Safety of our Customers and Employees,” a Southwest spokesperson said.
Amadeus has been called the information technology “backbone” for global airlines, including British Airways, Lufthansa Group airlines, Air France, Qatar Airways, Cathay Pacific and Southwest.
Amadeus blamed an unspecified “third party” for Friday’s incident.
“Amadeus briefly experienced a technical issue today affecting Southwest Airlines, originating from a third-party technology provider. Our teams took immediate action and worked closely with the provider to restore normal operations. We apologize for any inconvenience caused,” a spokesperson told The Post.
Similar problems hit United and Delta Airlines on Tuesday. A United spokesperson said its vendor also suffered a technical hiccup that prevented customers from using its systems, according to the report.
