The low-cost airline has informed clients who have booked affected flights of the cancellations via email. It said on its website that up to 50 flights per day, equivalent to 2%, had been cancelled over a six-week period.

Among those affecting Luxembourg were the London Stansted connection on 18 September.

The other cancelled flights we know about:

• On 20 September, Milan Bergamo flight 5836.
• On 21 September, Stansted-Luxembourg route (FR2860) and in the other direction (FR2861).
• On 23 September, Lisbon-Luxembourg (1791) flight and return (1792).
• On 1, 8, 15, 22 October, Porto to Luxembourg (2862) and return (2863).

Ryanair is offering refunds or the option to reschedule flights free of charge.

According to The Guardian, the cancellations come because of an error in planning pilot holidays related to a loss of pilots to a rival airline.

However, Ryanair denied this was related to a pilot shortage. It said in a press statement: “Ryanair is not short of pilots--we were able to fully crew our peak summer schedule in June, July and August--but we have messed up the allocation of annual leave to pilots in September and October because we are trying to allocate a full year’s leave into a 9 month period from April to December. This issue will not recur in 2018 as Ryanair goes back onto a 12 month calendar leave year from 1 January to 31December 2018.”

Meanwhile, thousands of disgruntled passengers posted comments on Facebook, some sharing stories of stranded wedding guests and groom and lost money on refundable accommodation.

For further information on how to rebook, receive a refund or to see the full list of cancelled flights, visit www.ryanair.com.