Thousands of Airbus planes are returning to normal service after being briefly grounded following a warning that solar radiation could interfere with onboard computers.

The aerospace giant - based in France - said about 6,000 of its A320 planes had been affected, with most requiring a quick software update. Some 900 older planes need a replacement computer.

On Saturday, French Transport Minister Philippe Tabarot said the updates "went very smoothly" for more than 5,000 planes, and fewer than 100 still needed the update.

Airbus CEO Guillaume Faury apologised for what he called "logistical challenges and delays".

He said teams were working to ensure that updates are completed "as swiftly as possible".

On Saturday morning, several Air France flights in and out of Paris's Charles de Gaulle Airport were delayed or cancelled.

American Airlines said it expected "operational delays" but added that the vast majority of updates would be carried out by Saturday.

Delta Airlines said it believed the impact on its operations would be limited.

The UK Civil Aviation Authority said that airlines operating in the country worked through the night to carry out the update and air traffic had not been seriously affected.

London's Gatwick Airport reported "some disruption", while Heathrow said it had not experienced any cancellations.

Manchester Airport said it did not anticipate significant problems, and Luton Airport reported that there was "no expected impact".

British Airways and Air India are understood not to be heavily impacted by the issue.

On Saturday, Easyjet said it had completed the update on a "significant number" of its aircraft, and planned to operate as normal.

Wizz Air is also running as normal, having rolled out updates overnight.

In Australia, budget airline Jetstar cancelled 90 flights. Most of its aircraft have now undergone the update, but some disruptions are expected though the weekend.

Air New Zealand grounded its A320 planes, but all fights have now resumed after the update was completed.

Airbus discovered the issue after a JetBlue Airways plane flying between the US and Mexico suddenly lost altitude and emergency landed in October. At least 15 people were injured.

The firm identified a problem with the aircraft's computing software which calculates a plane's elevation, and found that at high altitudes, data could be corrupted by intense radiation released periodically by the Sun.

As well as the A320, the company's best-selling aircraft, the A318, A319 and the A321 models were also affected.

Older planes that require new computers remain grounded. How long the replacement takes will depend on the availability of computers.