Ryanair shares soared as it saw its passenger numbers reach a record 86.4 million people.
Stocks in the budget airline hit an all-time high after a drive to improve its image helped attract a million extra passengers last month.
The Dublin-based carrier said passenger numbers in December jumped 20pc on a year before to 6.02 million.
Its load factor - a measure of how full the planes are - increased 7pc to 8pc over the last 12 months.
Rolling annual traffic to December rose 6pc to 86.4m customers, figures show that's more than the population of Germany.
The surge follows a drive by Ryanair to improve customer service by softening its stance on baggage charges and booking conditions after suffering two profit warnings at the end of 2013.
Its shares lifted more than 3pc on the Irish stock exchange today and have jumped 59pc over the past year.
Over the 12 months to December the airline, led by chief executive Michael O'Leary, said passenger numbers lifted 6pcto 86.4 million.
Ryanair's chief marketing officer Kenny Jacobs said the airline was benefiting from its Always Getting Better customer programme as well as lower fares and stronger forward bookings.
Read more: 10 changes that rebooted Ryanair
In August the carrier introduced its business class service, called Business Plus, which includes flexible tickets, priority boarding and premium seating.
The moves came after budget rival easyJet built up a sizeable business class base over recent years by selling additional services.
Last May Ryanair unveiled annual post-tax profits that were 8pc lower at €523m after a price war left average fares 4pc lower at a time of rising fuel costs. It was the firm's first drop in annual profits in five years.
But in November as demand increased it said it expected annual profits of up to €770m, a rise of 18pc on previous guidance.
The airline operates more than 1,600 routes from 68 bases across Europe. Last summer Ryanair launched 57 new routes and added four new bases in Athens, Brussels, Lisbon and Rome.