"These days most of the clogging is around the check-in lines," said Kenneth Button, a public policy professor at George Mason University who has studied airline luggage handling. "The main thing for off-site check-in is a case of convenience."

The top four airlines serving McCarran -- Southwest, US Airways, United and Delta -- now offer the service. Continental and Allegiant, the airlines in the fifth and sixth positions, are yet to offer it.

McCarran employees are recruiting more airlines to join because checking bags off-site can reduce backlogs at the airport.

The system uses a government-approved private contractor to pick up bags at participating locations and transport them to the airport ahead of passengers. There are plans to broaden the service to include check-in sites away from the Strip, which would make it more convenient for locals. But airport officials don't have an estimate for when they would add new sites.

Other baggage handling improvements at McCarran include a $12 million project that will increase the capacity of eight of 16 Terminal 1 baggage carousels 18 percent, improve the flow of foot traffic and install new signs to make it easier for passengers to find their bags.

McCarran is also one of just two airports worldwide that uses radio frequency identification tags to track bags on site.

The airport also installed a $150 million system of automatic explosive detection devices that replace sport utility vehicle-size screening devices in the airport concourse that sprung up in the wake of the Sept. 11, 2001, terrorist attacks. The federal government paid 75 percent of the cost.

Contact reporter Benjamin Spillman at bspillman@reviewjournal.com or (702) 477-3861.