“You’re not going to see masses signing up,” said Cindy Rosenthal, a company spokeswoman, “but there is clear interest in business travelers using this.”  The program requires people to provide fingerprints or an iris scan upon enrollment, and to submit to a background check conducted by the security agency and the Department of Homeland Security. When applicants are approved, their biometric data is placed on a plastic card; at the airport, their iris scan or fingerprints are matched against the card.  The system is not perfect, and has its detractors. Members must still have their carry-on luggage scanned by X-ray machines, which makes some airports question whether the extra effort is worth the expense and trouble. A few airports have turned down the system because officials fear that it will make regular security lines longer by reserving lanes for registered travelers.  “If anything, it will cause backups in other lines,” said Mike Boyd, the president of an aviation consulting firm in Evergreen, Colo. “I think it will die under its own weight.”  The federal government paid for five other airports — in Los Angeles, Minneapolis, Boston, Houston and Washington — to try out the program last year with a total of 10,000 enrollees. After the trials were evaluated, the program was approved, and a number of airports are in the process of applying.  But Orlando, Florida’s busiest airport, was eager to participate even after it was not chosen for the experiment, so it hired Verified Identity Pass to set up the program under the name Clear.  Chuck Carothers of Jackson, Tenn., who is not a program member and was plodding through Orlando’s security line, said he thought the concept was not necessarily a deterrent.  “People interested in terrorism obviously could purchase something like this,” he said, “and find a way around it.”  Howard Simon, executive director of the American Civil Liberties Union of Florida, agreed, saying background checks were not fail-safe. “It presumes that we have a complete and accurate database that consists of every terrorist,” Mr. Simon said. “When you’re dealing with the lives of several hundred people on a flight, that’s a presumption that makes me rather insecure.”  Amy Green contributed reporting from Orlando, Fla., for this article.  A version of this article appears in print on , on Page A10 of the New York edition with the headline: Prescreening Draws Interest As Lines Grow At Terminals. Order Reprints| Today's Paper|Subscribe
Orlando International Airport is the site of the nation’s only express security program, which lets prescreened fliers whisk through a special lane.