American Airlines said Tuesday it fixed an outage in its main reservations system that disrupted travel for thousands of passengers whose flights were delayed or canceled.
The computer system was fully restored by 3:30 p.m., but it caused continued flight delays and cancellations throughout the remainder of the day. More than 670 flights nationwide and more than 35 in Chicago were affected, said Mary Frances Fagan, the American Airlines spokeswoman in Chicago.
"It is important to note we see no evidence that today's technical outage is related to the tragic events in Boston," Fagan said, referring to explosions Monday at the Boston Marathon.
American asked the Federal Aviation Administration to halt its flights until 4 p.m. Flights on regional affiliate American Eagle heading to Dallas, Chicago or New York's LaGuardia Airport were stopped as well.
A spokeswoman for the Chicago Department of Aviation was not immediately available for comment.
Stranded passengers used social media to flood the airline with complaints. On Twitter, American was sending out apologies.
Passengers described long airport lines and frustration at the lack of information from airline employees.
"Tensions are high. A lot of people are getting mad. I've seen several yelling at the American agents," said Julie Burch, a business-meeting speaker who was stuck at Dallas-Fort Worth International Airport waiting for a flight to Denver. "Nobody can tell us anything."
Terry Anzur, a TV news consultant from Los Angeles who was also stranded at DFW, said American Airlines gate employees were doing everything the old-fashioned, manual way because their computers were useless.
"No one at the counter can do anything. They can't check people in," Anzur said. "The airline is at a dead halt."
American's problems on Tuesday were reminiscent of what United Airlines passengers endured on several days last year. United experienced computer glitches after combining its reservations system with that of Continental after the two airlines merged. On one day in August, 580 United flights were delayed and its website was shut down for two hours. Another outage in November delayed 636 flights.
American was offering free reservations changes and refunds for stranded passengers.
• Daily Herald Business Writer Anna Marie Kukec contributed to this report.