Microsoft outage causes mass airline disruptions. Here’s what to know. [Video]

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 1,300 flights had been canceled as of 10 a.m. Eastern Time, while more than 3,600 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 …