Low-cost carrier Norwegian saw its first quarter losses rise from 800 million NOK (£72.5m) last year to 1.5 billion (£136m) this year, which it blamed on higher fuel costs, tough competition and a stronger krone.
A later Easter, which fell in March in 2016 but in April this year, also led to a shift in income, it said.
The airline carried 6.7 million passengers in the first three months of the year, a 14% increase. Its strongest growth was in the US, Spain and France.
It said its global growth strategy will provide economies of scale and lower unit costs.
During the first quarter, unit costs excluding fuel fell by 4% and debt was cut by 1 billion NOK.
CEO Bjorn Kjos said: “In this quarter, we particularly see the effects of higher fuel costs combined with a strengthened krone against the British pound, euro and Swedish krone, which accounts for almost half of our sales.
“In addition, the figures are affected by the fact that Easter was not in the first quarter, like last year.
“At the same time, we are filling aircraft and attracting more passengers both in new and more established markets. Our long-haul operation is now well established, proving that customers want affordable fares and new aircraft on intercontinental routes.”
Norwegian launched 39 new routes during the first quarter, including routes between the US and Ireland, Northern Ireland, Scotland and Norway. In April, the company announced three new intercontinental destinations from London Gatwick to Singapore, Denver and Seattle.
The airline has today announced that it has extended its loyalty programme to enable members to earn points at 1,200 online retailers including Tesco, Marks and Spencer and John Lewis. Points can be used to pay for flights.