Up to 3,000 jobs across pilots and cabin crew are to be cut at Ryanair.

The budget airline group announced that a restructuring programme could also involve unpaid leave and pay being slashed by up to 20%, as well as the closure of "a number of aircraft bases across Europe" until demand for air travel recovers.

Chief executive Michael O'Leary, whose pay was cut by 50% for April and May, has agreed to extend the reduction for the remainder of the financial year to March 2021.

Ryanair said its flights will remain grounded until "at least July" and passenger numbers will not return to 2019 levels "until summer 2022 at the earliest".

Brian Strutton, general secretary of pilots' union Balpa, said: "There has been no warning or consultation by Ryanair about the 3,000 potential job losses and this is miserable news for pilots and staff who have taken pay cuts under the Government job retention scheme.

"Ryanair seems to have done a U-turn on its ability to weather the Covid storm.

"Aviation workers are now facing a tsunami of job losses. The UK Government has to stop daydreaming and keep to the promise made by the Chancellor on 17 March to help airlines, or this industry - vital to the UK economy - will be devastated."

Ryanair expects to operate fewer than 1% of its scheduled flights between April and June, and carry no more than half of its original target of 44.6 million passengers between July and September.

For the 12 months to the end of March 2021, its forecast is that it will carry fewer than 100 million passengers. Its target for the period was 154 million.

The airline group said it is in "active negotiations" with Boeing to cut the number of planned aircraft deliveries over the next 24 months.

It expects to report a net loss of more than 100 million euros (£87 million) between April and May, with "further losses" in the following three months.

The statement went on: "Ryanair entered this unprecedented Covid-19 crisis with almost 4 billion euros (£3.5 billion) in cash, and we continue to actively manage these cash resources to ensure that we can survive this Covid-19 pandemic, and more importantly the return to lower fare flight schedules as soon as possible.

"Our customers can look forward to more low air fares as we are forced to compete with flag carrier airlines who have received 30 billion euros (£26.2 billion) in state aid 'doping' to allow them to sustain below-cost selling for months after this Covid-19 crisis has passed, as it certainly will over the coming months."

Mr O'Leary said that customers may have to wait up to six months for cash refunds for cancelled flights.

He told the BBC: "In normal times we process about 10,000 refunds a month. These aren't normal times. Our offices are essentially closed.

"Yet, we have still now managed to increase the processing capacity to about 10,000 refunds a week.

"We have a backlog of about 25 million refunds, they can't be processed automatically because it's individual customers' money.

"Every customer will get a cash refund if they want a cash refund, but they will have to bear with us. It is going to take many weeks and months to process this backlog of refunds.

"Certainly we will have all the March refunds done within a month or two. The April refunds will have been done within two or three months.

"The May refunds may take three to six months.

"We simply have a gigantic problem. We didn't cancel these flights out of choice.

"These cancellations have been imposed on us by government, almost out of nowhere.

"But, we will, I can guarantee you in Ryanair, every customer will receive a cash refund if they want it."

Airlines around the world are facing a struggle to survive due to the coronavirus pandemic.

On Tuesday it was announced that up to 12,000 British Airways workers will lose their jobs, which is more than one in four employees.

Sir Richard Branson has warned that Virgin Atlantic will collapse unless it receives Government support.