WASHINGTON • A new passenger screening program to make check-in more convenient for certain travelers is being expanded to Lambert-St. Louis International Airport, the government said Wednesday.

The program will be expanded to 27 other American airports at the same time.

There will be no cost to eligible passengers, who would no longer have to remove their shoes and belts before they board flights.

The airports include the three used by hijackers to launch the terror attacks in September 2001: Washington Dulles International Airport, Newark Liberty International Airport in New Jersey and Boston's Logan International Airport.

The Transportation Security Administration's program, already in a test phase in seven other airports, is President Barack Obama's first attempt at a passenger screening program responsive to frequent complaints that the government is not using common sense when it screens all passengers at airports in the same way. Under the new program, eligible travelers have the option to volunteer more personal information about themselves so that the government can vet them for security purposes before they arrive at airport checkpoints.

Participating travelers will walk through a dedicated lane at airport security checkpoints. They will provide the TSA officer with a specially marked boarding pass. A machine will read the barcode, and travelers deemed "low risk" will likely be allowed to keep on belts, shoes and jackets and leave laptops and liquids in bags when being screened.

Not everyone is eligible to participate in the program, which is already being tested at airports in Atlanta, Dallas, Detroit, Miami, Las Vegas, Los Angeles and Minneapolis-St. Paul. Eligible travelers are some of those who participate in American and Delta airlines' frequent flier programs, as well as travelers in three other trusted traveler programs run by the Customs and Border Protection agency, which do charge fees to participate. About 336,000 passengers have been screened through the program since the testing began last year, according to the Transportation Security Administration.

By the end of 2012, the government expects select passengers in frequent flier programs for US Airways, United and Alaska Airlines to be eligible to participate. The program is expected to be operating in Reagan National Airport near Washington, Salt Lake City International Airport, John F. Kennedy International Airport in New York and Chicago's O'Hare International Airport by the end of March.

The program is expected to be operating at Lambert and these airports by the end of 2012: Baltimore-Washington International Thurgood Marshall Airport, Charlotte Douglas International Airport, Cincinnati/Northern Kentucky International Airport, Denver International Airport, Fort Lauderdale-Hollywood International Airport, Houston's George Bush Intercontinental Airport, Honolulu International Airport, New York's LaGuardia Airport, Louis Armstrong New Orleans International Airport, Puerto Rico's Luis Munoz Marin International Airport, Orlando International Airport, Philadelphia International Airport, Phoenix Sky Harbor International Airport, Pittsburgh International Airport, Oregon's Portland International Airport, San Francisco International Airport, Seattle-Tacoma International Airport, Florida's Tampa International Airport and Alaska's Ted Stevens Anchorage International Airport.