United Airlines will begin offering a second daily nonstop flight between San Francisco and Hong Kong, beginning Oct. 26. The additional service will give customers the choice of midday or late-night departures from both airports. Patrick Quayle, vice president of international network, said the additional flight offers customers more flexibility and convenience when planning travel to one of the world’s largest business markets. The carrier’s new evening departures from San Francisco give customers a morning arrival in Hong Kong, and the new evening departures from Hong Kong arrive in San Francisco in the evening. The two flights combined provide passengers with more options to connect to 80 destinations beyond San Francisco. The new flight is part of an international expansion that will include seasonal nonstop service to Melbourne, Australia in October and new seasonal service to New Delhi in December.