Airports, however, said the disruption was limited.
Passengers are enduring long waits at check-in desks after the outage on Thursday morning.
Quoting Singapore Airlines, the report said that the airline became aware of the global outage of some of its systems at about 5.30pm on Thursday.
Such network problems are not at all unusual, but they're usually confined to specific airlines and airports.
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The situation appeared normal when ST arrived at Changi Airport at about 8.30pm.
Southwest Airlines's and British Airways's support page was particularly busy. Other airlines did not appear to be experiencing delays either. This includes tagging luggage and issuing boarding passes.
The issue is affecting airlines around the world, including those operating at Heathrow and Gatwick. The outage affected more than 130 airlines who all use the system to help manage flight reservations and luggage services.
Air France said that it had experienced problems for 15 minutes and that its systems were slowly coming back online.
Out of frustration, fliers tweeted images of their predicaments at the affected airports, with a number of these images depicting lengthy queues. After a few minutes, the spokesman confirmed that the "glitch" had been fixed. The failure was due to a software error that is used by worldwide companies in the field of air transport.