DALLAS (AP) — The CEO of Southwest Airlines Co. said yesterday that the low-cost carrier could be forced to put the brakes on growth because revenue isn't rising as fast as expected.Southwest has been growing about eight percent a year by adding planes and serving more cities, but it might have overshot the runway. Occupancy on its planes has fallen, and it can't raise fares enough to cover rising fuel costs.

Chief executive Gary Kelly said company officials set their 2007 plans assuming a stronger economy, "and if that's not going to be the case then we'll need to make some adjustments".

Southwest is still a growth company, Kelly declared, but eight percent "is not a magic number." He said it was logical to think that "if the revenue environment is weaker perhaps we should grow slower, and that's just something that we're thinking through".

Continental Airlines Inc.'s chief financial officer disputed Kelly's view that air-travel demand has slowed. Jeffrey J. Misner said demand is still strong — if fares are low enough.

"There are plenty of folks out there that really do want to fly ... we don't see any demand weakness; it's really a revenue issue," Misner said.

Continental has also been expanding its capacity for international and domestic flights. Rivals have criticised that growth, especially on US flights, arguing that too many airplane seats are depressing fares.

Misner said Continental needed to increase its domestic flying partly to serve its international routes.

Continental also announced that yesterday it reached a deal with Boeing Co. to delay the delivery of six jets in 2009 until 2010. The Houston-based airline still plans to take delivery of 30 planes in 2008 and 24 in 2009.

Kelly and other airline leaders spoke at an investor conference in New York.