Regulators in Europe made the Airbus A320 fix mandatory late Friday|Laurent ERRERA|CC BY-SA 2.0

Airbus ordered urgent repairs on 6,000 A320-family jets, grounding more than half the global fleet and disrupting travel during one of the busiest holiday weekends.

The company issued the recall after investigators linked a JetBlue A320’s sudden altitude drop to solar flares corrupting flight control data. Regulators in Europe made the fix mandatory late Friday.

Airlines across the United States, Europe, India, South America, and New Zealand warned of delays and cancellations.

American Airlines said 340 of its 480 A320s need the repair, which takes about two hours. Several others, including IndiGo, Lufthansa, easyJet, and Avianca, also began pulling aircraft from service.

Avianca, hit hardest, paused ticket sales through December 8.

Most jets will return quickly after reverting to earlier software, but more than 1,000 aircraft may also need hardware changes, stretching the already overwhelmed maintenance shops.

Despite the timing and strain, analysts expect many repairs to be completed overnight or between flights.