SANTA ROSA -- Horizon Air, the Alaska Airlines subsidiary operating all commercial flights in Santa Rosa, had the highest operating profit margin among all regional airlines in the third quarter of 2011, according to new federal data.

Horizon Air had a 9.1 percent margin on $8 million in third-quarter operating profit, and Alaska Airlines's margin was 18.4 percent on $220 million in earnings in that July--September period, according to the federal Bureau of Transportation Statistics.

Horizon Air's margin improved from negative 15.7 percent in the second quarter and positive 7.7 percent in the third quarter of 2010.

Round-trip fares from Charles M. Schulz--Sonoma County Airport averaged $272.70 per person in the third quarter of last year, up 1.6 percent from the second quarter and 7.2 percent from a year before. Average U.S. fares during the third quarter of 2011 were $361.

Regional airlines like Horizon Air focus on flights connecting to various hubs around the country, where Alaska Airlines and other national carriers operate on a hub-and-spoke model.

Horizon Air operates five nonstop flights out of the Sonoma County Airport, serving Seattle, Portland, Los Angeles and Las Vegas. Nonstop service to San Diego is scheduled to begin in June, coinciding with the cessation of service to Las Vegas.

Airline travel at Sonoma County Airport reached an all time high in February, with 14,996 passengers representing a 5.4 percent increase from the prior year.