Turkish Airlines (search) said on Friday it has ordered an additional eight 737-800 (search) aircraft from Boeing Co. (BA), part of its plan to more than double its fleet in the coming years.

Last year Turkish Airlines (THY) announced plans to purchase 15 of the single-aisle 737-800s and took an option to buy another eight, as well as ordering 36 aircraft from Boeing's European rival Airbus.

"Turkish Airlines has decided to issue a definite order for the optional eight B737-800 planes under the framework of its agreement ... with Boeing," THY said in a statement to the Istanbul Stock Exchange on Friday.

"This brings the total number of planes that are being purchased from Boeing to 23," a spokeswoman for THY said.

A spokeswoman for Boeing also confirmed THY was exercising the options on eight planes, adding to the 15 ordered last September.

"We expect to finalize the order for (the) eight more in a couple of weeks," she said.

The eight planes are valued at about $524 million at list prices, though discounts are common in the industry.

THY has said it plans to increase its fleet to more than 100 aircraft by 2008. It agreed last year to buy 12 Airbus A321-200 and 19 A320-200 single-aisle planes and five A330-200s widebody aircraft from Airbus (search), which is owned by the European Aeronautic Defense & Space Co and Britain's BAE Systems Plc.

Around 25 percent of the shares in state-controlled Turkish Airlines are traded on the local bourse following a December public offering. By 1237 GMT the shares were up 1.3 percent at 7.65 new lira.

The government has said it plans additional offerings of THY under its multi-billion dollar IMF-backed privatisation program but has not set any timetable for further floats.

High oil prices trimmed the carrier's profits to 75 million lira (around $55 million) in 2004, despite a rise of 16.2 percent in the number of passengers.