Global aviation is in turmoil as Europe's Airbus ordered the immediate repair of 6,000 of its widely used A320 aircraft, in a widespread recall affecting more than half of the world's fleet, coinciding with the busiest travel weekend of the year in the US and already causing disruption to flights around the world.

The fix for the identified problem mainly involves rolling back to older software, but it must be done before the planes can fly again, according to a bulletin to airlines seen by Reuters. Several airlines have said the fixes could cause delays or cancellations.

Which airlines are affected by Airbus' decision?

Here are the most significant disruptions reported by airlines as of 07:33 GMT, in alphabetical order:

Aer Lingus: The Irish carrier reported that a limited number of aircraft were affected.

Air France: The airline announced that it is canceling 35 flights.

Air India: Air India, which has 113 affected aircraft, has completed a software fix on 42 aircraft. Some flight delays are expected, but no cancellations.

Air India Express: Twenty-five aircraft need software fixes, India's civil aviation regulator said.

Air New Zealand: The New Zealand airline expects some cancellations to its services.

American Airlines: The world's largest A320 carrier said it expects some operational delays but reduced the number of aircraft needing the software fix to 209 from 340 it had previously forecast.

ANA Holdings: The Japanese carrier canceled 65 flights on Saturday.

Avianca: The Colombian carrier announced that the recall affected more than 70% of its fleet, inevitably causing significant operational disruptions over the next 10 days. Avianca has closed ticket sales for travel dates through December 8.

Delta Airlines: The American carrier expects any operational impact to be limited.

Flynas: Saudi Arabia's low-cost airline expects some flight delays.

IndiGo: India's largest airline has completed a software fix on 143 of its 200 aircraft, the civil aviation regulator said. IndiGo warned of some delays.

Korean Air: The South Korean airline announced that work on 10 affected aircraft will be completed by Sunday morning.

Latam Airlines: The carrier said a limited number of aircraft needed software fixes.

Lufthansa: The German airline expects a small number of flight cancellations or delays over the weekend.

Turkish Airlines: The Turkish airline announced that eight A320 aircraft will return to service after completing the required actions.

United Airlines: The airline expects minor disruptions to some flights, after it announced that six aircraft were affected by the recall.

Viva: The Mexican airline announced that its fleet will be affected by the software update, but no timeframe has yet been set for when the aircraft will be ready to fly again.

Wizz Air: The European low-cost airline announced that the software update was applied overnight to all affected A320s and no further problems are expected.