Low-cost airline easyJet carried 5,884,304 passengers in December - 5.5% up on a year ago - despite an increase in cancellations.
The load factor was 91.4% - 1.5 percentage points up on last time.
The airline carried 81,634,343 passengers in 2017 - 9.6% up on the previous year.
The load factor was 93.0% - up from 91.5% in 2016.
There were 580 cancellations in December compared with 330 in December 2016.
The main contributors to this were adverse weather conditions causing c. 400 cancellations with runway closures making up the majority of the remaining cancellations and some impact from industrial action.