Bullish Boeing 737-700 operator Southwest Airlines has unveiled it is evaluating a possible introduction of the larger 737-800.

While the carrier says no final decision has been made, it stresses given Boeing's long lead time from order to delivery it needs to finalise plans by 1 December to support deliveries beginning in early 2012.

"While the aircraft introduces additional complexities to our operation, we believe our existing network could be enhanced by converting some of our future 737-700 deliveries to 737-800s," says carrier chief operating officer Michael Van de Ven on the carrier's blog site.

Southwest believes the -800 could supply scheduling flexibility by allowing additional capacity in high-demand, slot controlled or gate-restricted airports, says Van de Ven.

Southwest currently has a fleet of 544 aircraft -- 346 137-seat 737-700s, 25 122-seat 737-500s and 173 137-seat 737-300s. The 737-800 can be configured with 189 seats in an all economy configuration.

Southwest recently decided to accelerate the replacement of its 737 classics, converting six purchase rights to 2014 and exercising 25 737-700 options for delivery from 2011. However, the carrier stresses the changes will keep its fleet count essentially flat as it keeps its capacity growth conservative during the tenuous economic recovery.

It projects a modest capacity increase in 2011, while available seat mile growth for the third quarter of 2010 should reach 2.5% and 4.5% in the fourth quarter.

The fourth quarter estimates may look high in the context of constrained capacity growth, but analysts at JP Morgan recently pointed out that US carriers are coming off record utilisation lows for the fourth quarter of 2009.

Source: Air Transport Intelligence news