U.S. airline performance better - study

Passengers walk through terminal 1 while others wait at the United Airlines ticket counter at O'Hare International airport in Chicago November 24, 2010.

WASHINGTON (Reuters) - Overall performance of leading U.S. air carriers has gained for the third straight year, with performance declining in just one of four major areas -- customer complaints, according to a report released on Monday.

The annual Airline Quality Rating report showed improvement in the three other major areas, including on-time performance, baggage handling and involuntary denied boardings.

The overall score was the third best in 20 years of tracking, said a statement from Wichita State University and Purdue University.

Coincidentally, the report was released the same day one major carrier, Southwest Airlines, cancelled 70 flights as it continued to inspect Boeing 737 planes following the emergency landing on Friday of a jet with a hole in its fuselage.

The Airline Quality Rating is a joint project funded as part of faculty research activities at Wichita State and Purdue.

Regarding the higher number of customer complaints, Dean Headley, an associate professor at Wichita State, linked it to increasingly busier air travel.

"As the system adjusts to higher demand for air travel, more things are not going to go as planned for travellers," Headley said in the report.

(Reporting by Wendell Marsh; Writing by Jerry Norton; Editing by Barbara Goldberg)