Average fares at Pittsburgh International Airport rose 6.9 percent between the end of 2006 and 2007, according to figures released yesterday by the U.S. Department of Transportation.

The increase of fares from $281.55 in the fourth quarter of 2006 to $300.96 in the fourth quarter of 2007 was the 19th-highest jump in the country. The largest rise during that period was in Houston, where fares were up 16.2 percent.

Air fares across the country were up 4 percent, with 85 out of 100 top airports experiencing an increase during the period.

"I am going to say that's all oil related," said Bradley Penrod, executive director of the Allegheny County Airport Authority.

The rising price of oil, nearing $120 a barrel, is pressuring airlines to raise fares and add fees, such as US Airways' charge of $25 for a second checked bag, as a way of identifying new revenues.

Nevertheless, Pittsburgh remains affordable when compared to its peer cities. In fact, the average ticket price here in the fourth quarter ranked just 67th out of 100.

Cincinnati, by comparison, was No. 2, with an average fare of $531.73 -- the result of a local monopoly controlled by Delta Air Lines. Cleveland was 32nd, with an average fare of $343.44.

Since 2000, Pittsburgh International's air fare average is down 28.6 percent -- the largest drop of any city except White Plains, N.Y.

The falling prices since 9/11 can be attributed to the dramatic downsizing of US Airways, which gave up its monopoly hub here and slashed hundreds of flights as a way of surviving two bankruptcies.

US Airways' retrenchment created local opportunities for low-fare rivals such as Southwest Airlines and JetBlue Airways.

Mr. Penrod expects prices in Pittsburgh to remain "very competitive" despite the industry's woes. As recently as the third quarter of 2007, Pittsburgh' fares dropped 1.9 percent when compared to the same period the year before -- a larger discount than the national average during that time.

"The price fluctuations can vary greatly depending on what quarter is used," said Ken Zapinski, senior vice president of transportation and infrastructure at the nonprofit Allegheny Conference on Community Development.