San Diego, California - The U.S.-Mexico border is one of the world's most fortified international divides. Starting Wednesday, it will also be one of the only that has an airport straddling two countries.

An investor group that includes Chicago billionaire Sam Zell built a sleek terminal in San Diego with a bridge that crosses a razor-wire border fence to Tijuana's decades-old airport. Passengers pay $18 to walk a 390-foot overpass to Tijuana International Airport, a springboard about 30 Mexican destinations.

Target customers are the estimated 60 percent of Tijuana airport passengers who come to the United States, about 2.6 million last year. Now they drive about 15 minutes to a congested land crossing, where they wait up to several hours to enter San Diego by car or on foot. The airport bridge is a five-minute walk to a U.S. border inspector.

"It seems so much easier, so liberating," said Daniela Calderon, who flies from Tijuana four times a year to visit family in the central Mexican city of Morelia and has a friend drive her across the border from Riverside, California.

The only other cross-border airport known to industry experts is in the European Union - between Basel, Switzerland, and France's Upper Rhine region - but it carries none of the political freight of San Diego and Tijuana. Mexicans who ran across the border illegally overwhelmed the Border Patrol until the mid-1990s, when new fences and additional agents heralded a massive surge in U.S. enforcement on the 1,954-mile line with Mexico.