About one in five travelers planning to travel between Memorial Day and Labor Day will avoid airlines or cancel the trip entirely because of lengthy airport security checkpoint lines, according to a U.S. Travel Association survey.

But some say that appraisal could be too pessimistic and fails to consider that airlines may lower fares to sell tickets.

About 22% of respondents in the survey said recent media coverage of travelers waiting for hours at checkpoints discourages them from flying. A drop in travelers would hurt airline expectations for a record 231 million passengers from June 1 through Aug. 31.

"Hundreds of thousands of people are potentially reconsidering whether to get on an airplane," said Roger Dow, CEO of the U.S. Travel Association, an advocacy group for 1,200 businesses such as airlines, hotels and resorts. "Given the importance of travel to both our economy and our way of life, it is not an overstatement to call that a national crisis."

The survey follows blaring headlines about long lines and missed flights that resulted from a combination of fewer screeners, more travelers and tighter security. About 450 travelers were stranded overnight May 15 at Chicago O'Hare airport after missing flights because of the queues. American Airlines said 6,800 passengers missed flights during a single week in March.

Rob Britton, who spent 25 years in airline marketing and is now an adjunct professor at Georgetown University's McDonough School of Business, said he's skeptical of the survey's results. Long lines are already being trimmed at airports with the worst wait times, and airlines could advertise low fares if ticket sales fall, he said.

Congress this month allowed TSA to shift US$34 million within its accounts, to hire 768 officers by June 15 and pay more overtime. And airlines are providing staffers for non-security functions at checkpoints, such as reminding travelers what to put in bins or directing them to less crowded stations.

Still, lawmakers from both parties continued to blast wait times Wednesday. "Today we face a crisis at our airports," Rep. Michael McCaul, R-Texas, said at a House Homeland Security Committee hearing. "The American people are angry and frustrated."

Rep. Bennie Thompson, D-Miss., said that "asking passengers to arrive three hours before a domestic departure is unacceptable."

The U.S. Travel Association conducted the internet survey from May 19 to May 22. It questioned 2,500 adults from a panel of 1.2 million households chosen for geography, income, household size and market size.