A large delegation led by San Francisco mayor Gavin Newsom visited recently to celebrate the city's 30th anniversary as a sister city with Shanghai.

During the past three decades, the two coastal cities have been promoting closer ties through cooperation and communication.

San Francisco is the only US city to have a weeklong exhibition at the Expo 2010 Shanghai, says Newsom. During that week it will display some innovative projects by participating in the Urban Best Practice Area, a section of the Expo Garden that showcases cities' achievements in the area of eco-friendly innovation.

The San Francisco delegation's visit is sponsored by United Airlines, the operator of the largest direct flights between the US and China in terms of capacity. "Business and cultural relationships will boost our businesses in the future, as they will certainly benefit the city as well," said James P. Mueller, vice-president of the Pacific Region for United Airlines.

The Expo provides opportunities for many Chinese people to see a small piece of the outside world for the first time and for many US visitors who want to see Shanghai.

These connections and experiences are hoped to be the beginning of interests and inspirations of new business and communication that will continue to pay dividends for Shanghai for many years to come, said Mueller.

Operating the largest direct flights in capacity terms between the US and China, United Airlines is eager to tap deeper into China's aviation market.

The Star Alliance partner hopes to strengthen the ties with Shanghai, China's financial center and future international aviation hub, said a senior executive from the Chicago-based carrier.

Being one of the five Star Alliance founders, "United has worked closely with aviation alliance partner Air China to identify opportunities to serve the Shanghai market that Shanghai Airlines used to serve", said Mueller.

Former Star Alliance member Shanghai Airlines will become a SkyTeam member after its merger with China Eastern Airlines.

By the end of May, as many as 278 multinationals have set up their regional headquarters in Shanghai and more companies are trying to establish their branches here. Demand has soared as business travelers have asked for additional trans-Pacific flights.

Facilitating three non-stop flights to Beijing, two to Shanghai and four to Hong Kong every day for both business and leisure customers, United is in a very good position to relish the growth in the Chinese market, said Mueller. United is the first and oldest company to serve passengers from China to the US since 1986, and the traffic between the two nations continues to grow.

"We would like to have the opportunity to serve more frequencies and more destinations within China," said Mueller. He said United has been advocating an "open skies" agreement and the signing of the agreement will loosen restrictions on bilateral flights between China and the US.

UAL Corp, the parent of United Airlines, began a merger with Continental Airlines in May through a stock swap valued at more than $3 billion, and created the world's largest carrier. After the merger, United has expanded its daily non-stop flights to Shanghai from two to three by connecting to the west, east and central part of the US.