Angry customers have taken to social media to complain about airline Ryanair, vowing they would never book a flight with the company again, following mass cancellation of flights that are estimated to impact around 400,000 passengers.

Ryanair has revealed that it will cancel up to 50 flights every day for the next six weeks after it "messed up" the holiday rota for pilots.

Dismissing allegations that the company is facing a shortage of pilots, Ryanair's CEO, Michael O'Leary, said the company will "pay compensation to those passengers who are entitled to compensation, which will be those flights that are cancelled over the next two weeks".

Passengers whose flights have been cancelled have two options – they can apply for a refund, which will be processed within seven working days, or they can change or cancel their flights free of charge.

However, under European Union (EU) rules, if passengers are given more than two weeks' notice about a cancelled flight, the airline is not liable to pay compensation.

The company added that the decision to cancel flights was motivated by its need to improve punctuality, which has fallen from 90% to below 80% in the first two weeks of September.

Some people have strongly criticised the airline, claiming the way it was handling the situation was "appalling".

Twitter user Dan Harvey said that, although he thinks the cancellations will not affect him directly, he will never fly with Ryanair again.

"I do not appear to have been affected – though not assuming anything - but [I am] appalled by this level of customer service, lack of clarity and unprofessional approach," he told IBTimes UK.

" We absolutely will never book with Ryanair again – not worth the risk even if the flights are cheaper."

Another user, Stephen West, said the flights cancellations "ruined" his mother-in-law's "first ever trip away" and vowed to never buy a Ryanair ticket again.

Simon Elliott said he was "disappointed" to be charged extra for changing flights.

Pressure on Ryanair mounted as the company refused to publish a full list of flights it is going to cancel. The airline initially published a list of flights affected until this Wednesday (20 September).

It later said that a new list of cancelled flights would be published on Monday (18 September) and that affected passengers would be notified via email. However, both customers and customer groups said they needed a longer notice.

The company later published a list of cancelled flights until 28 October.