Norwegian Group airlines handled almost 2.7 million passengers on increased capacity in September.
Norwegian Air accounted for the bulk of carryings at 2.3 million while regional offshoot Wideroe flew almost 400,000.
The load factor at Norwegian Air was up 1.4 percentage points year on year to 86.6% as the airline operated an average of 89 aircraft last month as rose by two per cent.
The group exercised an option to expand an order for new generation Boeing 737 Max 8 aircraft and 10 new routes from Billund in Denmark during the month.
Chief executive Geir Karlsen hailed September as “a strong month in terms of both passenger numbers and load factor”.
He added: "This confirms that we have an attractive network well adapted to our customers’ travel requirements
“This has been an especially active month. I am very pleased that we could confirm we will be exercising our option to expand the Boeing order by 30 aircraft.
“This will be pivotal to our ongoing fleet renewal and underlines Norwegian’s growth ambitions in the years ahead.
“We launched our summer programme on 10 September and added several new and exciting destinations, including 10 new international routes from Billund, Denmark.
“The booking momentum is encouraging, with high loads during the autumn holiday periods, and with demand for winter and Christmas travel increasing.”