SAN DIEGO — 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 to Tijuana International Airport, a springboard to about 30 Mexican destinations.

Target customers are the estimated 60 per cent of Tijuana airport passengers who come to the United States, nearly 3 million a 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.