Southwest Airlines has been looking to the future during its annual general meeting in New York, with concerns over rising fuel prices topping the agenda.

Chief executive Gary Kelly went as far as to suggest potential increases in the cost of fuel in 2011 posed a greater threat to the success of the airline than that of consolidation among competitors.

Pictured: Southwest Airlines is the world’s largest low-cost carrier

He went on to argue airlines must scale back growth plans in the medium-term, while also keeping more cash and less debt.

Kelly also confirmed to investors Southwest had changed its order with US aerospace giant Boeing, substituting 20 of its 737-700s with 737-800s.

Southwest famously flies only 737s, with the streamlined fleet reducing costs for training employees and allowing the airline to avoid stocking spare parts for different planes.

Southwest Airlines chief executive Gary Kelly looks forward to 2011

Kelly said the order change “represents many exciting opportunities for our employees and our customers”.

The 737-800s will “set the stage to bring more destinations into the realm of possibilities for Southwest to operate more economical aircraft, and to offer better scheduling flexibility in high-demand, slot-controlled or gate-restricted markets,” he continued.

The 737-800 model planes will come with full extended-range twin-engine operational performance standards, a quiet cabin and improved security features, the airline said.

Southwest will, however, add a second type of jet - the smaller Boeing 717 - when it completes its acquisition of AirTran Airways.