Ryanair claimed new customer service initiatives are starting to pay off as December passenger carryings topped a record five million.
Passenger numbers rose by 4% from 4.8 million in December 2012 to more than five million last month.
The increase meant that Ryanair saw annual carryings rise by 2% to 81.4 million passengers.
The budget carrier’s monthly load factor remained unchanged at 81%.
A spokesman said: “Ryanair carried a new record of over five million customers in December, thanks to the success of our lower fares, easier-to-use website and customer service improvements.
“Further service improvements are due to be rolled out over the coming weeks and months as Ryanair continues to lower prices and improve our industry-leading customer service in 2014.”
The airline released 100,000 seats in a new year seat sale promotion which runs until midnight on Monday (January 6), with prices starting at £16.99 on more than 1,000 routes, for travel on Mondays, Tuesdays, Wednesdays and Thursdays in February and March.
Investec analyst James Hollins told the Telegraph that Ryanair’s performance in December was “sound”, although he questioned whether the customer service improvements had much of an impact.
“More likely, the aggressive pricing undertaken ... has been the key driver of the passenger increase,” he said.