U.S. air travelers are deeply frustrated with the quality of service so they avoid taking trips, which cost airlines billions of dollars, according to a recent study by the Travel Industry Association.

Seventy-eight percent of respondents believe the air travel system is either "broken" or needs "moderate correction." Sixty-two percent said the system is deteriorating.

This comes at a time airlines are being hammered by high fuel costs. United Airlines, for example, announced earlier this month that it was cutting jobs and removing scores of fuel-guzzling aircraft from its fleet in an effort to cope.

Delays, cancellations and inefficient security screening were the top concerns.

The survey found 28 percent of air travelers had avoided at least one trip in the past year to due air travel problems. The Travel Industry Association estimated 41 million trips were avoided, including 29 million leisure trips. Total cost of lost trips was estimated at $26.5 billion.

Air travelers also expressed little optimism about positive changes anytime soon. Almost half said they did not think things were likely to improve in the near future; nearly 60 percent of frequent travelers saw no improvement.

The survey of 1,003 air travelers was conducted by Peter D. Hart Research and The Winston Group from May 6-13. The statistical margin of sampling error is plus or minus 3.2 percentage points.

Business Editor Tom Mast can be reached at tom.mast@trib.com, or call 307-266-0574.