According to an article in business week Boeing is planning on changing the design of their 737, which is famously the only plane that Southwest Airlines operates. The 737 is also famous for being very simple to maintain and fly. The change in design hasn't been officially announced, but Boeing has stated that they will be improving the fuel economy of the plane, perhaps at the cost of simplicity of maintenance and operation. The improvement in fuel economy will hopefully enable the airline to cut prices and operate more efficiently. But the added complexity could create a scarcity of pilots capable of flying the plane. If the scarcity of pilots increases and the demand stays the same the price of a ticket would increase. The same goes for complex maintenance. Just like the scarcity of pilots increases so would the scarcity of mechanics. Mechanics would demand higher wages if the skill required to maintain the planes increases. All of which translates to less efficiency for the first year or so after the switch. Changing to a more fuel conscious jet would pay off in the long run because after a while the training will become standard and will be expected in pilots and mechanics. Because the initial cost will lessen over time the choice to change to a more fuel efficient plane is more profitable than the next best thing which is to keep using the same plane.