ISTANBUL – National flag-carrier Turkish Airlines, which aims to carry 20 percent more passengers in 2010, said on Thursday it would buy 20 planes from U.S. planemaker Boeing as it rapidly expands its fleet.

The airline said it would purchase 10 B737-800 planes and 10 B737-900 ER planes for delivery between 2011 and 2014, with an option to take 15 more of the same models for delivery between 2013 and 2015.

The 737 is a short-to-medium range plane with a capacity of around 200 passengers, according to Boeing’s website.

Turkish Airlines flew 25.1 million people in 2009, an increase of 11 percent and making it Europe’s fourth-biggest airline by passenger numbers, as it boosted its lucrative transit business.

The airline has ambitions to become Europe’s number three and fly 30 million passengers in 2010.

The airline flies to destinations across Europe, but also central Asia, Asia and across the Middle East. Last month it ordered 20 planes from Airbus for delivery between 2011 and 2012, with an option for a further 10 in 2013.

By 1000 GMT its shares traded flat at 5.60 lira, outperforming the Istanbul stock index which traded down 0.9 percent.

The airline’s stock rose 427 percent in 2009, massively outperforming the index which rose almost 100 percent. Of 14 analysts to follow the stock, eight rate it “buy” or “outperform”, four “hold” and two “underperform”.