Europe’s third-largest low-cost carrier Norwegian saw June carryings rise by 21% to more than 2.3 million passengers.
The airline operated 99.8% of its scheduled flights in June, with 83.4% departing on time.
The on-time performance was affected by industrial action among air traffic controllers in France.
The load factor was 82.5% in June, up 2.9 percentage points.
Norwegian took delivery of a Boeing 737-800, and a 787 Dreamliner in the month.
The airline, which started budget flights to the US from Gatwick last week, will take delivery of 14 Boeing 737-800s and four 787s this year.
Norwegian chief executive Bjørn Kjos said: “I’m pleased that we keep increasing the load factors even with major capacity growth.
“This proves that our offer of quality flights at affordable fares is welcomed by the customers. We continue to attract new customers in markets outside Scandinavia, in line with our international strategy.”