Scandinavian airline SAS on Friday reported a 4.2 percent rise in passenger traffic in May and said market growth was good but unpredictable.
The airline, half-owned by the governments of Sweden, Norway and Denmark, said its passenger load factor rose by 1.9 percentage units in May to 75.3 percent.
"The response to market campaigns is still good and forward booking levels are well above last year's level, but premium bookings are weaker on certain routes," the group said in a statement.
"Overall, the market growth continues to be good, but remains unpredictable due to added capacity in certain markets, risk in the global economy and continued high jet fuel prices," it added, saying this added uncertainty to the yield outlook.
The currency adjusted yield -- or revenue per unit -- fell 3.4 percent from a year ago in April, the latest month for which figures are available.