Wizz Air saw passenger carryings increase by almost a quarter last month over December 2018.
The eastern and central European low cost carrier flew 3.3 million passengers against 2.6 million in the same month the previous year.
The growth in passenger numbers came as the load factor improved to 89.4% from 88.8% year-on-year.
The airline reported a 2% reduction in CO2 emissions to 59.5 grams per passenger/km for the month.
The December performance gave the airline a total rolling total of 39.8 million passengers, annual growth of 17.7%.
The result came as Wizz Air opened new routes from Yerevan in Armenia and Paris Orly airport.