The old \u201cIT glitch\u201d was reportedly the cause of British Airways\u2019 multi-continent check-in delays on Monday. Angry travelers waited in check-in queues for hours while the airline fell back on the old school method of handwriting records, boarding passes and baggage labels.British Airways has been rolling out a new check-in system since last year; a BA spokesperson described the check-in delays as \u201cteething problems.\u201dAt first, BA claimed the glitch causing check-in delays was not a worldwide problem, but a \u201cpatchy\u201d problem. While the glitch in the check-in system affected more than people in the U.K., travelers took to Twitter to complain about long delays in at least San Diego, Chicago, Atlanta, San Francisco, Rome, Las Vegas, Phoenix, Vancouver, the Bahamas, D.C., Seattle, Zurich, and Mexico City.A letter given to delayed British Airways\u2019 travelers in San Francisco said the airline was \u201cexperiencing problems with the computer systems\u201d and would use a \u201cmanual fallback process.\u201d Apparently British Airways needed about 30 minutes to set up the pen and paper method. Yet some travelers waited in check-in queues for hours.British Airways released a statement announcing, \u201cOur IT teams are working as hard as they can to quickly fix a problem with our check-in system. This has affected a number of our airports. We are sorry for the delays some customers are experiencing as they check in for their flights.\u201dLater, British Airways said some flights had been cancelled on Monday \u201cdue to operational reasons\u201d but that specialists were \u201cworking to resolve this issue.\u201d Customers were advised to check in online before reaching the airport.Newcastle native Trevor Todd told NBC the captain of his delayed flight "made an announcement blaming the airline's recently introduced \u2018Fly\u2019 software used for check-in and bags at airports.\u201d Todd called the tarmac with unclaimed bags chaotic, adding that he had \u201cnever seen anything like this in 20 years of flying.\u201dApproximately 323 British Airways flights were delayed on Monday, according to tracking by Flight Aware. Although the airline claimed check-ins at Heathrow and Gatwick airports were back to normal today, Flight Aware shows another 288 flights delayed so far. Tweeters also disputed the back to normal check-in claim.The British Airways site still states, \u201cCheck in may take a bit longer than usual, so we would encourage customers to check in online before they reach the airport. We are sorry for the delay to your journey.\u201dOther airline delaysBritish Airways passengers were not the only ones to experience delays on Monday; London City Airport tweeted there was a \u201cdisruption to all flights due to protestors at the airport.\u201d The protest was part of the Black Lives Matter movement; protesters reportedly blocked the runway for six hours until police removed and arrested them.Last month, Delta Airlines suffered a global outage after an equipment failure in Atlanta led to the shutdown of its computer systems. Three weeks before that, Southwest Airlines had to cancel thousands of flights after a notebook-sized router failed at a data center in Dallas and it took 13 hours to reboot its systems.