Washington ? More airline passengers bumped, more bags lost and fewer on-time flights. For the third year in a row, those problems grew worse for the industry, according to annual study that rates airline quality.

“They just don’t get it yet,” said Dean Headley, an associate professor at Wichita State University and co-author of the study being released today.

One upside, researchers said, was that the number of complaints about airlines has stabilized since hitting a five-year low in 2005.

The study does not include information from recent weather-related flight delays such as the ones that left JetBlue and United Airlines planes idling for hours on taxiways.

An industry spokesman does not expect travel woes to improve anytime soon.

“We’re going to see more delays and those delays translate to cancellations, mishandled bags and unhappy passengers,” said David Castelveter, spokesman for the Air Transport Association, a trade group for the major U.S. carriers. “It’s not a pretty picture.”

Castelveter blamed the majority of delays on bad weather. Making matters worse, he said, more planes are going to be in the air in the coming years and the air traffic control system is not capable of handling the rate of growth.

Congress, he said, needs to provide more money to update the system so it better can handle the increased traffic and weather problems.

The Airline Quality Rating report, compiled annually since 1991, looked at 18 airlines and was based on Transportation Department statistics. The research is sponsored by the Aviation Institute at University of Nebraska at Omaha and Wichita State University.