Southwest Airlines Co. is famous for operating just one type of plane, the Boeing 737, which is often seen as an asset by keeping maintenance and training simple.

The company is waiting to learn about the Boeing Co.'s decision regarding the fate of the workhorse jet. The aircraft manufacturer is deciding whether to modernize the plane installing a more fuel-efficient engine or start afresh by manufacturing a new aircraft that might be quite different.

It might take years to develop a new plane, which could also increase the complexity of scheduling and training pilots and performing maintenance.

There was a conference call taking place between analysts and Southwest CEO Gary Kelly on Thursday, where analyst named Ray Neidl of Maxim Group asked the CEO whether his airline might go for buying Airbus jets if Boeing does not go for changing the engine of the 737.

Gary Kelly stated that Boeing hasn't given them an answer. He further stated that if Boeing told them that wont be seeing one more fuel-efficient 737 for another twenty years that probably would cause to change the mind of the company. South west loves the 737 and it would love for it to be more fuel-efficient.

Southwest has expectations of breaking their record of 737-only model after completing its pending take over of AirTran Airways and taking on AirTran's smaller Boeing 717 jets. Kelly further said that experience will teach the Airlines to operate a fleet with more than one type of plane.

Though officials of Southwest Airlines Co. gave their airline shining reviews for 2010 profits and stated of an optimistic outlook for early 2011, they admitted on Thursday that rising fuel prices are causing them concerns