Washington ? Hand sanitizer makes it through security in one airport, then it’s confiscated at another. Screening lines back up because only two of six lanes are open. And then there’s the occasional all-too-intimate patdown.

Those complaints and other frustrations make the nation’s airport security agency about as popular as the IRS.

Indeed, only the Federal Emergency Management Agency, still suffering from its mishandling of Hurricane Katrina, ranks below the Transportation Security Administration among the least-liked federal agencies, according to a new Associated Press-Ipsos poll.

TSA tied with the perennially unpopular tax collectors in a favorability ranking of a dozen executive branch agencies.

“I am so frustrated with TSA that I am ready to stop flying,” one traveler wrote in a Sept. 7 complaint filed with the agency. “I’m sure this doesn’t matter to you because my tax dollars are already paying you.”

The AP poll, conducted Monday through Wednesday, found that the more people travel, the less they like TSA. But it also found that 53 percent of air travelers think TSA does a “very” or “somewhat” good job.

The inconvenience of security was the top complaint of air travelers, mentioned by 31 percent of those who had taken at least one trip in the past year. That figure rose to 40 percent for those who have taken five to 10 trips.

TSA’s parent agency, the Department of Homeland Security, also ranked at the bottom of an index of consumer satisfaction released this week, supplanting the IRS as the prime subject of grumbling in that survey. The authoritative American Customer Satisfaction Index questioned 10,000 people about their experiences with the federal government.

TSA officials say they understand the frustration and are working to minimize hassles. They say while it can be annoying, airport screening is essential because intelligence reports show aviation remains a top target for terrorists.

A review of complaints the traveling public lodged with TSA in September helps explain the low standing. While passengers generally understand TSA’s mission, they could do without certain parts of the pre-boarding experience.

Take, for example, a mother and daughter traveling out of the Dallas/Fort Worth airport on Sept. 4. In an e-mailed complaint to TSA, the mother said the TSA screener was rude and inconsiderate. While she was in secondary screening, the mother was made to face away from her daughter. “Someone could have taken my daughter,” the woman wrote. “I understand you have to have security, but your people don’t need to be rude!!!”

Nearly 9,000 such complaints flowed into TSA between January and October of this year, and the agency made a selection of them available at the request of The Associated Press.

Paul C. Light, professor of public policy at New York University, said he’s not surprised that TSA and the IRS are tied for low public esteem.

Yet he defended TSA as misunderstood, because it’s highly visible yet can’t brag about its successes. “It’s an agency that’s damned if it does, damned if it doesn’t,” Light said.

TSA responds to every complaint it receives, said spokeswoman Ellen Howe, adding that each complaint is forwarded to the federal security director at the airport in question.

In the cases AP reviewed, the most common response was a form letter, apologizing for inconveniences, often blaming the problem of long lines on the local airport and forwarding complaints about inappropriate patdowns to the airports where they occurred.

Out of all the contacts TSA receives, only about 2 percent are complaints, Howe said.

Howe also defended the agency’s 43,000 screeners and said the public needs to know that they are “good people motivated by the mission.”

“Our officers take a lot of disrespect from the public,” Howe said. “These people are on the front lines and they deserve our respect.”

Screeners make about $30,000 a year.