The airline said net profit for the period was 435.9 million Norwegian kroner ($74 million), compared with 628 million kroner a year earlier. It said it spent just over 100 million kroner on replacing the 787s, dubbed Dreamliners, and compensating delayed passengers.
Third-quarter sales rose 15 percent to 4.88 billion kroner from 4.22 billion in the same period 2012.
Norwegian has grown rapidly in recent years, expanding international traffic and adding new bases.
Still, the airline said it experienced increased competition in leisure markets and that the warm late summer weather in northern Europe had a negative effect on sales during the quarter.