Scandinavia's SAS Group is to order 50 more Airbus A320neos to replace Boeing 737s and older A320 jets.
SAS had previously indicated that the A320neo was the prime candidate for a further fleet expansion.
The airline had already ordered 30 of the type, of which 17 have been delivered.
SAS says it will take 15 aircraft from the new batch of 50 for delivery over 2019-21. It says that these have been "secured through declarations of intent with lessors".
The other 35 aircraft will be delivered directly from Airbus, up to 2023.
No engine selection has been made for the additional aircraft, although SAS's current A320neo fleet is powered by the CFM International Leap-1A.
SAS has also placed options for another five A320neos as part of the agreement.