Planes were stuck on the ground for hours across the United States on Wednesday, leading to thousands of canceled and delayed flights after a government system used to give pilots safety and other information broke down overnight.The White House initially said that there was no evidence of a cyberattack behind the outage that ruined travel plans for millions of passengers.More than 21,000 flights were scheduled to take off in the U.S. Wednesday, mostly domestic trips, and about 1,840 international flights expected to fly to the U.S., according to aviation data firm Cirium.John Cox, a former airline pilot and aviation safety expert, said there has been talk in the aviation industry for years about trying to modernize the NOTAM system, but he did not know the age of the servers that the FAA uses.“I told him to report directly to me when they find out.” Buttigieg acknowledged the flight delays and cancellations caused by the outage, but emphasized “the main thing I want everybody to understand is that every step of the way safety is going to be our north star, as it always is.” “We are now pivoting to focus on understanding the causes of the issue,” he said."