Continental Airlines has expanded its mobile boarding pass service to Frankfurt Airport, becoming the first U.S. carrier to offer paperless boarding passes outside of the United States.

The service allows customers to receive boarding passes electronically on their mobile phones or PDAs and eliminate the need for paper boarding passes.

"Our customers have told us they want a convenient option, especially those that travel a lot,? said Julie King, a spokeswoman for Continental, Houston. ?This mobile boarding pass is another way for customers to expedite their travel."

Mobile boarding passes display a two-dimensional bar code along with passenger and flight information, and scanners at the security check point validate the authenticity.

The technology prevents manipulation or duplication of the boarding passes and heightens security.

Continental was the first carrier to offer paperless boarding passes in the U.S. in a pilot program with the Transportation Security Administration that began in December 2007.

The airline currently offers mobile boarding passes at 35 airports, including its hubs in New York, Houston and Cleveland, with plans to expand to more U.S. and international destinations.

Continental operates daily nonstop flights to Frankfurt from both its New York hub, Newark Liberty International Airport, and its Houston hub at Bush Intercontinental Airport.

Continental Airlines is the world's fifth largest airline. Continental, together with Continental Express and Continental Connection, has more than 2,400 daily departures throughout the Americas, Europe and Asia, serving 130 domestic and 132 international destinations.

?We like to be available to all kinds of customers in all different ways, it?s all about options,? Ms. King said.