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 commercial air traffic that critics say has long been overworked and underfunded.

The pause on flights across the country highlighted what aviation experts say are glaring weaknesses at the agency, long considered the world’s premier aviation regulator. The F.A.A. has struggled to quickly update systems and processes, many of which were put in place decades ago, to keep up with technological advancements and a sharp increase in the number of flights and passengers.

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A big part of the problem, aviation experts said, is that Congress has not given the F.A.A. enough money to do its many jobs properly, and the agency has sometimes been slow to make change even when it had enough resources. The agency’s budget was about $18.5 billion in 2022 — less than it was in 2004 after adjusting for inflation.

“This is an agency that has been chronically and critically underfunded, not for years, but for decades,” said William J. McGee, a senior fellow for aviation at the American Economic Liberties Project, a research and advocacy group that has criticized consolidation in the airline business.

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