It flew 9.3 million passengers in December, up three percent compared with 12 months earlier.
Ryanair suffered a turbulent end to 2017, with it was forced to cancel 20,000 flights through to March this year, mainly because of botched holiday scheduling for pilots.
The fiasco triggered pilots' demands for better working conditions and representation, with some departing for other carriers.
The discontent also saw Ryanair hit by its first-ever strike by pilots, with German staff staging a short stoppage ahead of Christmas.
This despite Ryanair finally making moves to formally recognise pilots' unions.
Ryanair has meanwhile set itself the goal of transporting 200 million passengers annually by 2024.