Major US Carriers Ground Flights Due to Communication Issues

Major U.S. carriers, including American Airlines, Delta Airlines, and United Airlines, issued ground stops on Friday morning due to communication issues. This came less than an hour after Microsoft resolved a cloud services outage that had impacted several low-cost carriers.

It was not immediately clear whether the decision to keep flights grounded was related to the earlier Microsoft cloud outage. In addition to American and Delta, United and Allegiant Air also grounded flights.

The FAA did not immediately respond to Reuters’ request for comment.

Earlier, low-cost carriers Frontier Airlines, Allegiant, and SunCountry reported outages affecting their operations. Frontier announced late Thursday that it was in the process of resuming normal operations and that its ground stop had been lifted. The airline cited a “major Microsoft technical outage” as the cause of its temporary disruption. SunCountry mentioned that a third-party vendor affected its booking and check-in facilities, without naming the company.

U.S. Secretary of Transportation Pete Buttigieg stated that the department was monitoring the flight cancellations and delays at Frontier, emphasizing that the agency would hold the company and all other airlines accountable for meeting passenger needs.

“The Allegiant website is currently unavailable due to the Microsoft Azure issue,” Allegiant said in a statement to CNN. The airline did not immediately respond to Reuters’ request for comment.

On Thursday, Frontier canceled 147 flights and delayed 212 others, according to data tracker FlightAware. Allegiant saw delays for 45% of its aircraft, while Sun Country experienced delays for 23% of its flights. The companies did not provide details on the total number of flights impacted.

Microsoft reported that its outage began around 6 pm ET on Thursday, affecting a subset of customers using multiple Azure services in the Central U.S. region. Azure is a cloud computing platform that provides services for building, deploying, and managing applications and services. Microsoft also mentioned it was investigating an issue impacting various Microsoft 365 apps and services.