US aerospace giant Boeing said Tuesday that it had a firm order from Turkish Airlines for 70 Boeing single-aisle 737 aircraft in a deal valued at $6.9 billion at list prices.
The order, originally announced as a commitment in early April, was finalized Tuesday and "is the largest Boeing order in Turkish Airlines's history," Boeing said in a statement.
It includes an option to buy 25 additional 737s, valued at $2.5 billion at list prices.
The Turkish flag carrier is buying 40 737 MAX 8s and 10 737 MAX 9s -- Boeing's new re-engined fuel-efficient version under development -- and 20 Next-Generation 737-800 jets.
The airline plans to double its current fleet of 215 Airbus and Boeing airplanes and expand the destinations it serves by 50 percent.
In mid-March, Turkish Airlines announced it would buy up to 117 aircraft from Airbus, Boeing's European arch-rival, in a deal estimated at $9.3 billion.
Deliveries of the Airbus 320s and 321s were scheduled between 2015 and 2020.
Boeing said the Turkish Airlines deal brings the total number of 737 MAXs ordered since the program was launched in August 2011 to 1,285.
The Chicago-based company plans the first flight for the 737 MAX in 2016, with deliveries to customers starting in the fourth quarter of 2017.