Southwest airlines joining others in raising airfare prices:

PHOENIX, AZ—

As the price of oil rises across the board in the U.S., Southwest Airlines is joining the growing list of domestic airlines forced to raise the cost of airfare.

The company—which carries more domestic passengers than any other airline in the nation—has increased the price of round-trip airfare by an average of $10, not a very high number, but when considering it is the sixth-such time that airlines have raised fares in 2011 alone, it is easy to see the difference between the cost of a ticket now and just two months ago.

Southwest has long marketed itself as having some of the lowest fares in the industry and prides itself on its customer service, which includes such luxuries as no baggage fees and no penalties for changing itineraries online.  Many other airlines’ round-trip prices are widely influenced by those of Southwest, which consistently comes up at the top of travel sites that sort options by cost.

Now that the prices for jet fuel have risen to more than $3 a gallon—a rise of more than 50 percent over the last year—airlines are feeling the pressure of needing to offset the cost of running their planes.  While some airlines, such as Delta, tried implementing a $20 increase, many other major airlines agreed that raising fares by $10 would be more reasonable and not stand to deter travelers.

Many of the airlines held back on increasing the prices of flights that directly compete with Southwest, but once they saw that company raise fares—waiting three days after the others—they quickly did the same.  Industry analysts predict that now that the cheapest airlines are raising fares, the changes are likely to become permanent.