FORT WORTH, Texas—American Airlines said Wednesday it will take delivery of another six Boeing 737-800s in 2010, in an effort to speed up the replacement of gas-guzzling MD-80s in its fleet.

The move brings the total number of 737-800s expected to be delivered in 2009 and 2010 to 76 aircraft.

American said the deal is part of an amendment under its purchase agreement with Boeing, in which the airline exercised its right to buy 20 737-800s for delivery in 2009 and 2010. American said it has secured financing for about two-thirds of the Boeing 737-800 deliveries in 2009 and 2010.

While the carrier said it has the option to finance all of its 2009 deliveries under the deal, it declined to disclose any further details about the plan.

The airline said it still has “firm commitments” to its plan to take delivery of 11 737s in 2013, but it noted it is still evaluating opportunities to further speed up the fleet renewal process.

American announced plans in July to retire 30 MD-80s by the end of this year, along with 10 A300s and 26 Saab turboprop aircraft. It will also retire or remove 37 regional jets from service. The carrier plans to cut domestic flight capacity by 11 percent to 12 percent in the fourth quarter, after the peak summer season ends.