An FAA computer malfunction involving access to flight plans caused nationwide flight cancellations and delays Thursday, forcing travelers to scramble to make other arrangements or wait for hours at the airport.
The glitch was fixed by mid-morning, but travelers continued to feel the effects throughout the day.
The difficulties started when a single circuit board in a piece of networking equipment at a computer center in Salt Lake City failed around 5 a.m., the Federal Aviation Administration said in a statement.
The FAA said its computer system was up and running again by about 9 a.m. EST. But flights across the United States were being affected throughout Thursday and possibly longer. Airports in Europe weren't reporting problems.
That failure prevented air traffic control computers in different parts of the country from talking to each other.
Air traffic controllers were forced to type in complicated flight plans themselves because they could not be transferred automatically from computers in one region of the country to computers in another, slowing down the whole system.
The FAA's Kathleen Bergen said the technical difficulties didn't have an impact on air traffic control's contact with aircraft.
Controllers had "radio coverage and communications with planes" while the systems were down, she said.
Two large computer centers in Salt Lake City and near Atlanta were affected, as well as 21 regional radar centers around the country.
Hartsfield-Jackson Atlanta International Airport, the world's busiest, was particularly affected. The problem also exacerbated delays caused by bad weather in the Northeast, with airports in the Chicago, Washington, D.C., and New York metro areas reporting problems.
Some flights were more than two hours behind schedule. Airports around the South also reported delays and cancellations.
U.S. Sen. Charles Schumer said the country's aviation system is "in shambles" and the FAA needs more resources to prevent such problems from continuing.
"If we don't deliver the resources, manpower, and technology the FAA it needs to upgrade the system, these technical glitches that cause cascading delays and chaos across the country are going to become a very regular occurrence," he said in a statement.
Passengers were asked to check the status of their flights online before going to airports.
AirTran canceled at least 22 flights and delayed dozens more. Delta Air Lines was also affected. American Airlines spokesman Tim Smith said several hundred flights would be delayed.
Continental Airlines delays averaged about an hour during the early part of the morning. JetBlue Airways said 25 of its flights at Kennedy International Airport had average delays of 60 minutes and delays at other airports were up to 30 minutes. US Airways flights were no longer being affected by the glitch by midday.
Houston's two airports and Dallas-Fort Worth International Airport reported few delays but said things could get worse, especially for travelers headed east. Los Angeles International Airport also reported that delays were likely later in the day. Airports in Europe reported no immediate problems.
Houston's two airports and Dallas-Fort Worth International Airport reported few delays but said things could get worse, especially for travelers headed east. Los Angeles International Airport also reported that delays were likely later in the day.
The Associated Press contributed to this report.