CHICAGO (CBS/CNN) — Problems with the reservation system at Southwest Airlines prompted the FAA to issue a nationwide ground stoppage for the airline, affecting many flights at Midway and O’Hare airports, and other airports across the nation.

“The FAA issued a temporary nationwide ground stop at the request of Southwest Airlines while the company resolved a reservation computer issue. Please contact the airline for further details,” the agency posted on Twitter.

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In a statement, a Southwest Airlines spokesman said the company is “is in the process of resuming normal operations after a brief pause in our flight activity resulting from intermittent performance issues with our network connectivity Tuesday afternoon.”

“Our Teams are working quickly to minimize flight disruptions and Customer impact. We appreciate our Customers’ patience as we work to get them to their destinations. We ask that travelers use to check flight status or consult a Southwest Airlines Customer Service Agent at the airport for assistance with travel needs,” spokesman Dan Landson said in an email. “We do not have any indications this is a related to a cyber threat.”

The airline did not specify how many flights were affected by the problem, but CNN reports the aviation tracking website FlightAware says nearly 30% of Southwest’s schedule is canceled or delayed Tuesday. It said the airline has canceled 478 flights and delayed 528 flights.

According to the Chicago Department of Aviation website, at least 18 Southwest flights have been canceled at Midway International Airport on Tuesday, and 15 others have been delayed on Tuesday. At least four Southwest flights at O’Hare International Airport were delayed.

The technical problems for Southwest on Tuesday come after the airline’s third-party weather data provider experienced intermittent performance issues Monday evening, grounding planes and delaying travel across the United States.

Delta and Alaska Airlines also reported computer issues Monday that affected their ability to sell tickets.

Passengers across the country took to social media to express their frustration and demand answers after the issue left some people grounded, stranded and stuck on planes.

As the world has returned to pre-pandemic era air travel, flights have seen an uptick in issues, with the Federal Aviation Administration saying there have been 3,000 unruly passengers reported this year.

Southwest said the technical issue Monday prevented the transmission of weather information that is required to safely operate their aircraft.

“While the vendor worked to restore connectivity, we implemented a ground stop to protect the safety of our crews and customers,” the statement said.

Southwest said it was working to get all passengers to their destinations as quickly as possible.

Passengers were delayed, stranded

Chris Martin, who was traveling on Monday, told CNN he was delayed for over two hours on a Southwest Airlines flight from San Jose, California, to Austin, Texas.

After tweeting about the airlines outage issues and delays, he said he was able to board a flight but many others were not so lucky.

“Lining up to board now, apparently they are releasing the weather paperwork city by city. This was a 5:55pm departure, now 8:17pm out here,” Martin told CNN. “Twenty-two flights showing on the board delayed or canceled.”

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Jason Goran, another passenger who was traveling from San Diego, California, to Houston, said he sat on the plane for two hours due to the weather system outage.

“@SouthwestAir captain said we can’t take off because weather system for entire company is down?” Goran tweeted during the ordeal.

Goran said the flight was scheduled to take off at 5:50 p.m. PT. By the time he spoke with CNN, it was 8:17 p.m. PT.

“It feels like we are about to take off,” he said at the time. “They called us back to the plane but we haven’t pushed back yet.”

Patrick Miller said after boarding his flight from Phoenix to Portland, Oregon, passengers had to deplane and then re-board.

“From boarding to deplaning, it (took) two hours,” Miller told CNN.

He also tweeted about his delay, saying “Lots of hate being thrown at @SouthwestAir right now, but my flight attendants have been giving out water and people are allowed to deplane.”

People were losing their patience due to the delay, he said.

Other passengers, like Ryan Cesaitis, said they were able to take off and land, but ended up stuck on their planes as issues continued to plague the airline.

Cesaitis, who also shared his experience on Twitter, told CNN that he waited on the tarmac for 90 minutes after landing at Dallas Love Field from Phoenix.

Other airlines also experienced issues

Delta told CNN in a statement that its teams were working to quickly address a technical issue that made it difficult for customers to purchase flights on, the Fly Delta app and through the company’s Reservation Call Center.

The ability to check in for flights was not affected, according to the statement.

Alaska Airlines also experienced issues Monday. In a tweet to a customer, the airline said that its “booking page is down. Our team is working hard to get this resolved.”

message on the Alaska Airlines booking page read, “We are currently experiencing issues that affect shopping at, our mobile app and through our contact center. We are actively working with our partner that powers our shopping platform to resolve the issue. We apologize for the inconvenience. Please try again later.”

CNN reached out to Alaska Airlines for comment but has not yet heard back.

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(© Copyright 2021 CBS Broadcasting Inc. All Rights Reserved. The CNN Wire contributed to this report.)

CBS 2 Chicago Staff