How many Frontier flights were delayed or cancelled by the Microsoft outage?

The low-cost US airline Frontier was forced to cancel over 100 flights on Thursday after being significantly affected by a Microsoft outage. The Denver-based carrier also suffered a large number of delays.

How many delays and cancellations did Frontier suffer?

According to the flight-tracking website Flight Aware, Frontier cancelled 148 (19%) of its flights on Thursday. A further 211 (27%) were delayed. As of 3 a.m. ET on Friday, Flight Aware also listed 20 cancellations and nine delays for the day ahead, although it is unclear how many of these disruptions are due to the Microsoft incident.

What happened?

At around 8 p.m. ET on Thursday, Frontier announced major IT issues, saying in a statement: “Our systems are currently impacted by a Microsoft outage, which is also affecting other companies. During this time booking, check-in, access to your boarding pass, and some flights may be impacted. We appreciate your patience.”

Per widespread reports, the US’s Federal Aviation Administration (FAA) then revealed that Frontier had asked to put a hold on departures across the country, before lifting the ground stop shortly after 10 p.m. ET. At around 4 a.m. ET on Friday morning, Frontier tweeted: “The ground stop has been lifted, and our systems are gradually normalizing. We are in the process of resuming flight operations.”

What you can do if your Frontier flight was affected

In a statement on its website, Frontier said that passengers whose flights were either cancelled or delayed by more than 180 minutes are eligible for one of three options. They can: rebook onto another flight free of charge; cancel their booking and receive credit for use in buying a future Frontier flight; or cancel their booking and receive a full refund.

What has Microsoft said about the outage?

According to Microsoft’s Azure cloud software’s status report site, service was disrupted in the Central US region around 6 p.m. ET on Thursday. This included issues with “service management operations and connectivity or availability of services”.

Other carriers in the US, including Sun Country Airlines and Allegiant Air, also reported IT issues. Sun Country said trip-management functions on its website were “temporarily unavailable”, before later saying that services “are being restored”. Sun Country delayed 23% of flights on Thursday, per Flight Aware.

Meanwhile, Allegiant’s website remains down, with visitors to the page redirected to a message that reads: “The Allegiant website is currently unavailable. Thanks for your patience. Please try again in a few minutes.” 44% of Allegiant’s flights were delayed on Thursday, Flight Aware says.

Ground stop put out over “communication issue”

Early on Friday, an FAA advisory then revealed that a ground stop has been placed on all Allegiant flights, along with those operated by major carriers American Airlines, Delta Airlines and United Airlines, citing a “communication issue”. It is not clear whether this is related to the Microsoft outage.