Despite the goosing by soaring jet fuel costs, average airfares in Pittsburgh continued to decline last year as the king of the cut-rate carriers, Southwest Airlines, established itself in the local skies.

The average one-way fare at Pittsburgh International Airport skidded to $170 in the fourth quarter, down 3 percent from $175 in the fourth quarter of 2004, according to just-released data from the U.S. Department of Transportation.

The decline continued a trend in recent years reflecting the upheaval in the airline industry since the 9/11 terrorist attacks, price pressures from expanding discount carriers, and, locally, the retrenchment of US Airways, which severed the carrier's stranglehold in Pittsburgh where it charged monopoly-like prices.

The DOT data also showed that the Pittsburgh market recorded the biggest decrease in fares on any route in the country in the fourth quarter, with a round-trip ticket from Pittsburgh to Philadelphia plunging 65 percent, from $526 to $182. The plunge reflected the entrance of Southwest, which began serving Pittsburgh in May 2005.

The Pittsburgh to Hartford/Springfield route posted the 10th biggest decline, falling 31 percent from $506 to $346.

Despite the good news, the DOT study also showed that Pittsburgh remained among the country's most expensive cities for air travelers, placing No. 31 out of 120 markets surveyed.

The five most expensive markets were Cincinnati; Dallas/Ft. Worth; Memphis; White Plains, N.Y.; and Charlotte, N.C., according to the data, while the cheapest cities were Long Beach, Calif.; Tampa/St. Petersburg, Fla.; Chicago; Islip/Long Island, N.Y.; and Akron/Canton, Ohio.

Pittsburgh also claimed the second and third highest average prices in the country on short-haul routes -- $288 one-way to Boston and $282 to New York. Those averages, for the fourth quarter, undoubtedly will fall this summer now that JetBlue has begun offering service to both cities.

A separate report by the DOT's statistical arm released in April seemed to be at odds with the latest report, showing ticket prices rose in the fourth quarter from a year earlier both in Pittsburgh and for the nation as a stronger economy and an industrywide reduction in capacity had more passengers chasing fewer airline seats.

The Bureau of Transportation Statistics' Air Travel Price Index rose 8 percent for Pittsburgh, slightly less than the 9.1 percent increase logged nationwide. The methodologies for the two studies differ. The DOT analysis is based on fares on specific flights between domestic cities, while the price index is based on quarterly changes in domestic and international fares on comparable though not necessarily identical routes.