Norwegian's passenger numbers for June totalled 1.91 million, a 21% rise year on year.
"This is the highest number of passengers the company has carried in one single month," confirms the airline.
Revenue passenger-kilometres were up 35% as capacity rose 31%. Load factor climbed to 79.6%.
The 4% fall in revenue per available seat-kilometre "must be seen in conjunction with significantly longer distances flown, which also affects unit cost", says Norwegian's chief executive Bjørn Kjos.
At the end of the month, Norwegian took delivery of its first Boeing 787, which after flying on European routes for a month will be used for long-haul services from Oslo to Bangkok and New York.