HONG KONG -- United Airlines is "cautiously optimistic" about the outcome of U.S.-China negotiations on increasing the frequency of direct flights between the two countries.
Chicago-based carrier hopes to increase service between Shanghai and San Francisco

United Airlines operates four flights a week connecting Shanghai Pudong and San Francisco. © Reuters
HONG KONG -- United Airlines is "cautiously optimistic" about the outcome of U.S.-China negotiations on increasing the frequency of direct flights between the two countries.