(Reuters) - Major U.S. airlines issued ground stops on Friday citing communications issues, while other carriers, media companies, banks and telecoms firms around the world also reported system outages were disrupting their operations.

American Airlines, Delta Airlines, United Airlines and Allegiant Air grounded flights less than an hour after Microsoft said it resolved its cloud services outage that impacted several low-cost carriers.

It was not immediately clear whether the call to keep flights from taking off were related to an earlier Microsoft cloud outage.

In Australia, media, banks and telecoms companies suffered outages, which the government said appears to be linked to an issue at global cybersecurity firm Crowdstrike.

Crowdsourced website Downdetector showed outages at several banks and telecoms companies.

Crowdstrike ran a recorded phone message on Friday when Reuters contacted its technical support saying it was aware of reports of crashes on Microsoft's Windows operating system relating to its Falcon sensor, without mentioning Australia.

There was no information to suggest the outage was a cyber security incident, the office of Australia's National Cyber Security Coordinator Michelle McGuinness said in a post on X.

The outages rippled far and wide, with Spain reporting a "computer incident" at all its airports, while Ryanair, Europe's largest airline by passenger numbers, warned passengers of potential disruptions which it said would affect "all airlines operating across the Network," though it did not specify the nature of the disruptions.

AWS cloud service provider said in a statement that it was "investigating reports of connectivity issues to Windows EC2 instances and Workspaces within AWS."

It was not immediately clear whether all reported outages were linked to Crowdstrike problems or there were other issues at play.

(Reporting by Reuters bureaus; Writing by Tomasz Janowski; Editing by Emelia Sithole-Matarise)