Norwegian, which rejected two takeover bids from British Airways owner International Airlines Group, reported a 16% rise in April passenger numbers.
The low-cost carrier flew more than three million passengers last month over April 2017 as fares were slashed to boost carryings.
The result came as capacity soared by more than half due to a doubling of long-haul routes year-on-year.
This led to the load factor falling by 3.6 percentage points to 83%.
The figures were affected by an early Easter at the end of March and early April plus the introduction of new long-haul routes.
Chief executive Bjørn Kjos said: “We have a strong passenger growth this month, despite the effects of the Easter traffic.
“Our load factor is solid, and the company’s long-haul capacity has grown considerably since the same period last year, with a record high growth of 311% outside the Nordics.
“As a result of the capacity increase we have offered a high volume of low fare tickets to attract new customers, consequently impacting the yield this month.”
The third largest airline at Gatwick airline took delivery of one Boeing 787-9 Dreamliner in April out of a total of 11 due to join the fleet this year together with 12 Boeing 737 MAX 8s and two Boeing 737-800s.