There are warnings flights could be cancelled or delayed after Airbus requested immediate modifications to thousands of planes over its discovery that intense radiation from the sun could corrupt data crucial to flight controls.

About 6,000 planes are thought to be affected, about half the European aerospace giant’s global fleet, but it is understood most will be able to undergo a simple software update.

The UK’s aviation regulator said carrying out the updates would likely cause “some disruption and cancellations to flights”.

Airbus said the problem was discovered following a recent “incident” in the US involving an A320 family aircraft and apologised for disruption to passengers.

The incident, which happened on 30 October, involved a JetBlue Airways A320 making an emergency landing in Florida, after a sudden drop in altitude. At least 15 people were reported to have been injured.

The issue affects the A320 – its best selling aircraft – but also models from the same design fleet, including the A318, A319 and the A321.

It is understood that on around 5,100 Airbus planes, the issue can be addressed using a relatively simple software update which would typically take about three hours.

However, the remaining 900 aircraft which are older versions will need computers replaced and will not be allowed to carry passengers again until the job has been completed. The length of time that takes will depend on the availability of replacement computers.

Airbus said it acknowledged this will lead to “operational disruption to passengers and customers”, and has apologised.

Easyjet said said it was “expecting this to result in some disruption” but later added it had started and “already completed the software update on many aircraft”.

“We plan to operate our flying programme normally on Saturday and ask that customers travelling continue to monitor their flights on flight tracker,” a spokesman said.

“Safety is our highest priority and easyJet operates its fleet of aircraft in strict compliance with manufacturers guidelines.”

Wizz Air added some of its aircraft were among those that require updates and that it had scheduled the necessary maintenance, while Air India said the directive from Airbus could lead to delays.

American Airlines said 340 of its planes were affected and that it expected “some operational delays”, but added the vast majority of updates would be completed on Friday or Saturday. Delta Airlines said it believed the impact on its operations would be “limited”.

British Airways is understood not be be heavily impacted by the issue.

The Civil Aviation Authority [CAA], the UK’s aviation regulator, said only some airlines would be affected, with others not impacted at all.

“The requirement will mean the airlines flying these aircraft will in some cases have to change software over the days ahead or remain on the ground from Sunday onwards until the software has been changed,” the regulator said.

Tim Johnson, policy director at CAA, told the BBC: “That unfortunately may mean there is some disruption, some delays or cancellations over the coming days.”

Giancarlo Buono, director of aviation safety at CAA, added: “Passengers should check with their airline whether their flights are affected. Airlines have a duty of care to look after passengers when a flight is delayed.”

Transport Secretary Heidi Alexander said “the impact on UK airlines seems limited”.

“It is heartening this issue has been identified and will be addressed so swiftly, demonstrating the high aviation safety standards globally,” she added

The problem that can potentially affect the A320 family aircraft is that intense solar radiation at high altitudes can affect the working of the ELAC computer, which controls the elevators and ailerons. These are aerodynamic surfaces that are used to make the aircraft pitch up or down or roll to turn.

However, Airbus said the JetBlue incident was the only time this has actually happened.

The European Union Aviation Safety Agency (EASA) has issued an emergency airworthiness directive, ordering airlines to replace ELAC computers on the worst affected planes before carrying passengers again.

The EASA directive stipulated that as of 29 November, these planes can only fly passengers once they’ve been fixed. They will be allowed to make so-called “ferry flights”, without passengers, in order to get to a maintenance facility.

The A320 family are what is known as “fly by wire” planes. This means there is no direct mechanical link between the controls in the cockpit and the parts of the aircraft that actually govern flight. The pilot’s actions are interpreted by computers – which actually “fly” the plane.

Airbus has issued an alert to airlines requesting them to take “immediate precautionary action…in order to implement the available software and/or hardware protection and ensure the fleet is safe to fly”.