Live updates: Major U.S. air carriers ground flights as mass IT outage hits Windows users

American Airlines, United and Delta are grounding flights citing communications issues, according to the Federal Aviation Administration’s advisory page — as mass IT outages affect businesses across the world. The groundings come hours after Microsoft said it had resolved a cloud services outage that had forced a grounding of Frontier and Sun Country flights, though it is unclear if the groundings of departing flights from major air carriers are related. Cybersecurity firm CrowdStrike, in a recorded phone message, said it was aware of reports of Microsoft Windows errors related to its technology.