Microsoft and CrowdStrike are fighting against criticism from Delta Air Lines over a major tech outage last month that Delta blamed on the companies and said cost $500 million. Delta's CEO Ed Bastian said last week the global outage started with a faulty upgrade from CrowdStrike to Microsoft Windows machines. Microsoft's lawyer said Delta's key IT system is likely supported by other tech companies besides Microsoft. Microsoft lawyer Mark Cheffo accused Delta of making incomplete and misleading statements damaging Microsoft's reputation while questioning why Delta took longer than other airlines to restore business operations.