Severe winter weather hit flight punctuality by Norwegian Air in January.
Just three quarters (76.7%) of flights departed within 15 minutes of their scheduled time.
The level of disruption was disclosed as the Scandinavian carrier reported more than 1.1 million carryings and regional arm Widerøe flew 246,326. Norwegian operated an average of 63 aircraft last month.
Chief executive Geir Karlsen said: “Our operations during the winter season are affected by seasonal weather and particular winter storms.
“I would like to give thanks to the tireless effort of our colleagues, who have ensured that our disruptions are kept to a minimum, to the benefit of our many customers.”
The Norwegian Competition Authority approved the acquisition of Widerøe in December, with the transaction completed on January 12.
Karlsen said: ”For the first time, our traffic figures include those of Widerøe, and in total, Norwegian and Widerøe had 1.4 million passengers on board in the first month of the year.
“For Norwegian, it is very positive that the load factor increased by five percentage points compared to January last year.
“Demand to beach destinations continues to perform in the high-end of our expectations with many of our customers opting for some warmer Mediterranean weather.”
The group said it has hedged jet fuel “corresponding to approximately 50% of projected consumption at levels close to current forward prices”.