NEW YORK — A computer outage delayed thousands of travelers on Thursday and embarrassed United Airlines at a time when it is trying to recover from glitches earlier this year.
The two-hour outage held up morning flights around the globe, including five at Logan International Airport in Boston. It was at least the third major computer outage for the airline since June.
‘‘Does anyone have a Radio Shack computer or abacus to help United get their system fixed?’’ tweeted Lewis Franck, a motorsports writer flying from Newark to Miami. Some fliers waited nearly two hours.
Judd Shapiro of Nashua said he got to the gate at Logan but airline agents told him and other frustrated fliers that planes could land but not take off.
‘‘JetBlue is taking off, American is taking off, but United is on the ground,’’ he said. ‘‘I was having a flawless airport experience until I got to the gate.’’
United said the problem was fixed by 10:30 a.m. But early-morning delays can ripple through an airline network for the rest of the day; once a plane is late for one flight it can be hard to make up lost time.
United was not immediately able to say how many flights were delayed. A spokesman, Rahsaan Johnson, said few if any flights were canceled.
The problem was that dispatchers could not send flight information to about half of United’s mainline flights. Johnson said the problem affected planes that came from United, which merged with Continental in 2010. Planes that came from Continental, and regional flights on United Express, were not affected. All of them together run some 5,500 flights a day.
United’s biggest computer problem occurred in March, when its long-planned transition to a single computer system for passenger information caused delays and problems with frequent flier account balances. In August, 580 flights were delayed and the website was shut down for two hours because of a hardware problem.
Johnson said Thursday’s problems were not related to integrating the computer systems of the two airlines.
Chief executive Jeff Smisek acknowledged Oct. 25 that some customers avoided United over summer because of the computer problems. He said the airline fixed the problems by improving software and adding more spare planes to its system, among other things.
Thursday’s problems were exactly what United did not need, said an airline and travel industry analyst, Henry H. Harteveldt. “This event shows an unacceptable lack of planning at United,’’ he said. ‘‘This merger has been an outright disaster on almost every count. United must make some changes in its executive leadership, starting with the CEO.’’Katie Johnston of the Globe staff contributed to this report.