Tens of thousands of flights were delayed or canceled around Christmas when frigid weather and storms made travel treacherous. But the weather was mostly fine on Wednesday morning when flights across the country were halted because the Federal Aviation Administration’s system to alert pilots to safety issues went down.The F.A.A. said on Wednesday night that it had traced the outage to a damaged database file and that there was no evidence that it was caused by a cyberattack. The disruption was the latest example of serious problems in the aviation system and at the F.A.A., the agency responsible for safely managing all com …
