Airline passengers filed 11,445 complaints with the Transportation Department last year, an increase of more than one-fifth from 2011.
The rate of complaints per 100,000 passengers also rose, from 1.19 in 2011 to 1.43 last year.
A breakdown of that rate for the 14 largest U.S. carriers from a report being released Monday on airline quality by researchers at Purdue University and Wichita State University. The first rate is for 2012; the second for 2011.
—Air Tran: 0.91; 0.72
—Alaska: 0.51; 0.48
—American: 1.80; 1.46
—American Eagle: 1.27; 1.45
—Delta: 0.73; 1.23
—ExpressJet: 1.07
—Frontier: 1.05; 0.76
—Hawaiian: 0.89; 0.70
—JetBlue: 0.79; 1.08
—SkyWest: 0.88; 0.73
—Southwest: 0.25; 0.32
—United: 4.24; 2.21
—US Airways: 1.74; 1.91
—Virgin America: 1.50
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2011 rates were not available for ExpressJet and Virgin America.