Recently, Southwest Airlines and Boeing reached an agreement under which the LCC deferred delivery of five 737-700s slated to arrive in 2008-13 and exercised options for 25 additional -700s for delivery in 2013 and 2014.

The agreement is part of a broader strategy to slow its rate of growth. "In our continuing efforts to restore profit growth, we have adjusted both our fourth-quarter 2007 and full-year 2008 capacity plans to grow ASMs year-over-year by approximately 6%, or about two percentage points slower than previously planned," SWA said in a statement.

It originally had planned to take delivery of 34 737s next year. In addition to the five deferred aircraft, it said it is "exploring a variety of alternatives" regarding another 10 737s it had planned to take in 2008. It said net deliveries next year will total 19, or 15 fewer than its previous plan.

Separately, Boeing revealed that it sold three more 737s, three 777s and six 787s to unidentified customers, bringing the manufacturer's net orders for the year to 616 led by 267 737s.