Microsoft outage causes widespread airline disruptions and cancellations. Here’s what to know.

Air travel is experiencing disruptions across the globe on Friday morning due to a Microsoft outage for customers of its 365 apps, including many major airlines. 

In the U.S., more than 1,000 flights had been canceled as of 8 a.m. Eastern Time, while more than 1,700 flights have been delayed, according to FlightAware, a flight tracking service.

Airlines said the outage impacted the back-end systems they use to send key data, such as weight and balance information, required for planes to depart.

Air travelers posted images on social media of long lines at ticket counters, and “blue screens of death” — the Microsoft error page when its programs aren’t working — at screens at various airports. The issue was caused by a software update sent from cybersecurity firm CrowdStrike to Microsoft, and which it said it had identified in its systems and was working to resolve. 

“In a nutshell, this is PR nightmare for CrowdStrike and Microsoft and others get caught in this tornado along with millions of people currently stranded at airports around the globe,” Wedbush analyst Dan Ives said in a report.

Delta Air Lines

At about 7:50 a.m. Eastern Time, Delta said it resumed some flights after an airline-wide pause earlier on Friday morning due to the Microsoft outage. Delta had canceled about 330 U.S. flights as of 8 a.m., FlightAware data shows.

“We are working to resolve the issue as quickly as possible to resume operations,” Delta said in its statement.

United Airlines

United said it has been able to resume some flights, but warned customers to “expect schedule disruptions to continue throughout Friday.” About 150 United flights had been canceled as of Friday morning.

The airline added, “We have issued a waiver to make it easier for customers to change their travel plans via United.com or the United app.”

American Airlines

American said it has restarted its operations at about 5 a.m. Eastern Time. FlightAware data shows that about 279 American flights had been canceled as of roughly 8 a.m. 

—With reporting by Kris Van Cleave.