NEW YORK - Thousands of trips across the U.S. were canceled or delayed Wednesday once a government system that offers safety and other demand to pilots broke down, stranding some planes on the spurious for hours.

The White House said there was no evidence that a cyberattack triggered the outage, which upended travel plans for millions of passengers. President Joe Biden said he beleaguered the Department of Transportation to investigate.

The breakdown conveyed how much American air travel depends on an antiquated computer systems that generates alerts called NOTAMs — or Notice to Air Missions — to pilots and others.

Before a trips takes off, pilots and airline dispatchers must review the notices, which include details about weather, runway closures or creation and other information that could affect the flight. The systems was once telephone-based, with pilots calling dedicated flight ceremony stations for the information, but it has moved online.

The NOTAM systems broke down late Tuesday and was not fixed pending midmorning Wednesday, leading to more than 1,200 flight cancellations and more than 8,500 delays by early afternoon on the East Coast, according to the flight tracking website FlightAware.

Even once the Federal Aviation Administration lifted the order grounding planes, the chaos was expected to linger. More than 21,000 trips were scheduled to take off Wednesday in the U.S., mostly domestic flights, and about 1,840 international flights expected to fly to the U.S., according to aviation data firm Cirium.

Airports in Chicago, Los Angeles, New York and Atlanta saw 30% to 40% of trips delayed.

"There was a systems issue overnight that led to a spurious stop because of the way safety information was challenging through the system," Transportation Secretary Pete Buttigieg told a news conference. Although the problem was soon fixed, he warned that travelers could put a question to to see some effects "rippling through the system."

Buttigieg said his activity would now try to learn why the NOTAM systems went down.

Longtime aviation insiders could not recall an outage of such magnitude transported by a technology breakdown. Some compared it to the state shutdown of airspace after the 2001 terrorist attacks.

"Periodically there have been local copies here or there, but this is pretty significant historically," said Tim Campbell, a former senior vice president of air operations at American Airlines and now a consultant in Minneapolis.

Campbell said there has long been difficulty about the FAA's technology, and not just the NOTAM system.

Many of those controls "are old mainframe systems that are generally reliable, but they are out of date," he said.

John Cox, a archaic airline pilot and aviation safety expert, said there has been talk in the aviation diligence for years about trying to modernize the NOTAM rules, but he did not know the age of the servers that the FAA uses.

"I've been flying 53 days. I've never heard the system go down like this," Cox said. "So something current happened."

According to FAA advisories, the NOTAM system dedicated at 8:28 p.m. Tuesday, preventing new or amended notices from beings distributed to pilots. The FAA resorted to a telephone hotline to keep departures flying overnight, but as daytime traffic picked up, the phone rules became overwhelmed.

The FAA ordered all departing flights grounded early Wednesday morning, affecting all passenger and cargo flights. Some medical escapes could get clearance, and the outage did not capture any military operations.

Biden said that he was briefed by Buttigieg.

Buttigieg emphasized that "safety is causing to be our North Star, as it always is."

"We are now pivoting to place on understanding the causes of the issue," he said.

Passengers scrambled to commanded trips. Many said they had trouble finding out how long the delays would last.

"There is just a lot of frustration, a lot of confusion," said Ryan Ososki, who was trying to fly from Washington, D.C., to California for a conference. "I'm back to an hour and a half delayed (and) level-headed unclear as to whether or not I should be embarking because I'd now miss my connection flight."

Julia Macpherson was on a United escapes from Sydney to Los Angeles when she learned of possible delays.

"As I was up in the air, I got news from my dismal who was also traveling overseas that there was a powerful outage," said Macpherson, who was returning to Florida from Hobart, Tasmania.

Once she lands in Los Angeles, she level-headed has a connection in Denver on her way to Jacksonville, Florida.

She said there were no announcements on the escapes about the FAA issue.

Similar stories came out of Chicago, Washington, Atlanta and other major U.S. airports.

European escapes into the U.S. appeared to be largely unaffected. Carriers incorporating Ireland's Aer Lingus and Germany's Lufthansa said their schedules were unaffected.

It was the unexperienced headache for travelers in the U.S. who faced weather-related escapes cancellations over the holidays and a breakdown with staffing technology at Southwest Airlines.

Passengers also ran into long arrange, lost baggage, and cancellations and delays over the summer as move demand roared back from the COVID-19 pandemic and ran into staffing cutbacks at airports and airlines in the U.S. and Europe.

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