U.S.|Frontier Airlines Briefly Grounds All Flights Amid Microsoft Outagehttps://www.nytimes.com/2024/07/18/us/frontier-flights-grounded-microsoft.htmlAdvertisementSKIP ADVERTISEMENTA problem with Microsoft’s Azure system also hit check-in and booking systems at Allegiant and Sun Country Airlines.A major Microsoft outage grounded all Frontier Airlines flights on Thursday.Credit...Justin Sullivan/Getty ImagesJuly 18, 2024, 11:05 p.m. ETFrontier Airlines briefly grounded all flights on Thursday ami...