Norwegian Air is exercising an option to purchase 30 additional Boeing 737 Max 8 aircraft.
This brings the total firm order to 80 of the new generation aircraft for an undisclosed sum.
The airline and Boeing have agreed to adjust certain delivery dates, with the final aircraft in the order now scheduled for delivery in 2031.
Norwegian announced an agreement in May to acquire 50 B737 Max 8s, including an option for an additional 30 aircraft.
“The expanded order underlines Norwegian’s growth in the years ahead,” an airline statement said.
“The updated delivery schedule ensures an efficient and balanced renewal of Norwegian’s fleet, closely aligned with lease expiries and market developments.”
The order will provide a fuel-efficient fleet with lower operating costs compared to previous-generation aircraft.
Airline chief executive Geir Karlsen said: “This milestone aircraft order is on attractive terms and secures our fleet growth in a way that supports our planned growth and sustainability targets.
“By exercising the option and adjusting the delivery profile, we maintain flexibility while reinforcing our commitment to operating one of the most modern and fuel-efficient fleets in Europe.
“These aircraft will not only lower emissions but also provide our customers with an even better travel experience. We are pleased to extend our solid long-term partnership with Boeing through this order.”