Major U.S. airlines, including American Airlines (AAL.O), Delta Airlines (DAL.N), and United Airlines (UAL.O), implemented ground stops Friday morning due to communication issues, shortly after Microsoft resolved a cloud services outage affecting several budget carriers.
It remains unclear if the decision to halt flights was directly related to Microsoft’s earlier cloud outage (MSFT.O). Besides American and Delta, United Airlines and Allegiant Air (ALGT.O) also grounded flights.
The FAA had not responded immediately to Reuters’ request for comment.
Low-cost carriers Frontier Airlines, a subsidiary of Frontier Group Holdings (ULCC.O), Allegiant, and SunCountry (SNCY.O) reported earlier outages impacting their operations. Frontier later announced it was restoring normal operations and lifting its ground stop, attributing the disruption to a “major Microsoft technical outage.” SunCountry cited issues with a third-party vendor affecting its booking and check-in systems.
U.S. Secretary of Transportation Pete Buttigieg stated the department was monitoring flight cancellations and delays at Frontier, affirming that airlines would be held accountable for meeting passenger needs.
Allegiant acknowledged issues with its website due to the Microsoft Azure problem, but did not respond immediately to Reuters’ request for comment.
According to FlightAware, Frontier canceled 147 flights and delayed 212 others on Thursday, while Allegiant and Sun Country experienced delays affecting 45% and 23% of their flights respectively. Specific flight impact numbers were not disclosed by the airlines.
Microsoft reported that its outage, affecting a subset of customers using Azure services in the Central U.S. region, began around 6 pm ET on Thursday. Azure provides cloud computing solutions for application development and management.
In a separate statement, Microsoft confirmed it was investigating issues affecting various Microsoft 365 apps and services.
