Qantas and other major airlines around the world were hit by an outage of Amadeus' Altea travel booking software.
The outage, which was caused by an unspecified "network problem", has now been resolved, but not before causing some delays at airports and problems for customers wanting to check bookings.
Airport operators and airlines reported varying impacts, ranging from a few minutes up to half an hour.
Former VMware A/NZ managing director Paul Harapin was one of many affected, tweeting "massive queues in Hong Kong" airport due to the unavailability of check-in systems at the Qantas desks.
Other Qantas customers turned to social media when they could not check existing bookings or purchase new flights.
The Australian flag carrier attributed the issues to a "system outage [that] affected airlines globally". It was far from the only airline impacted by Amadeus' problems.
Dutch carrier KLM said it and Air France had been forced to delay 25 flights due to the outage.
British Airways, Lufthansa and Qatar Airways were also among the airlines that reported problems due to the Amadeus outage.
Airports, however, said the disruption was limited.
Frankfurt airport operator Fraport said on Twitter that Germany’s largest carrier Lufthansa and partner airlines had been hit by a problem for around 30 minutes in the morning which prevented bags being checked in, but said the issue had been resolved.
London’s Gatwick airport also said its airlines had some “brief issues” but were now operating as normal.
A spokesman for Groupe ADP, which operates and manages more than a dozen airports in the greater Paris region, confirmed airlines using the Amadeus system had been affected at the French capital’s Charles de Gaulle airport.
“We were no worse affected than other airports. It only lasted a few minutes,” the spokesman said.
In Washington, a spokesman for the Metropolitan Washington Airports Authority said Southwest Airlines reported a computer issue causing a few minor delays at Reagan National Airport of up to 16 minutes but there were no other issues at present.
Additional reporting by iTnews.