Airports across the United States slowly descended into chaos early Friday after a worldwide tech outage disrupted flights and stranded passengers.
At least five airlines — Allegiant Air, American, Delta, Spirit and United — issued ground stops, according to the Federal Aviation Administration.
“The F.A.A. is closely monitoring a technical issue impacting IT systems at U.S. airlines,” the agency said in a statement. “Several airlines have requested F.A.A. assistance with ground stops for their fleets until the issue is resolved.”
It was unclear how long the ground stops were expected to last, but it was causing some headaches for travelers.
American Airlines said in a statement on social media on Friday morning that it was aware of a tech issue with its vendor affecting multiple carriers.
“American is working with the vendor to resolve the issue as quickly as possible,” the airline said. “We apologize to our customers for the inconvenience.”
Similarly, Delta said in a statement on its website that it had “paused” flights.
At Denver International Airport, large screens typically used to detail flight arrivals and departures were flashing blue error messages, leaving some passengers confused and uneasy about their travel plans.
Frank Tingley, a 42-year-old data analyst, was among thousands of travelers stranded at Denver International Airport on Friday morning.
“I’m not good actually,” he said, adding that he first noticed an issue when airport staff had difficulties scanning tickets for his flight to Boston Logan International Airport.
Mr. Tingley said he was allowed to board the plane but after further complications and delays emerged, passengers deplaned.
“The general mood is that people are finding a quiet corner and just trying to hunker down,” he said.
As of early Friday, dozens of flights were already canceled at LaGuardia Airport in New York and Hartsfield-Jackson International in Atlanta, according to FlightAware, a database that tracks flight information.
Passengers at other airports around the country, including some at Ronald Reagan Washington National Airport and Dallas Fort Worth International Airport, quickly voiced their concerns on social media. Many posted videos of crowded terminals packed with disgruntled passengers waiting with their bags.
On Thursday, a major outage in the Microsoft network briefly grounded Frontier Airlines. Other low-cost carriers like Allegiant Air and Sun Country Airlines were also affected.
Microsoft said the problem had affected multiple systems for customers in the central United States.