United Airlines will restart nonstop service between San Francisco and Shanghai from next week, the airline announced on Monday. The carrier will operate four weekly nonstop flights with Boeing 777-300ER aircraft between San Francisco and Shanghai's Pudong International Airport beginning from October 21. The flights from San Francisco to Shanghai will be operated on Wednesdays, Fridays, Saturdays and Sundays; while return flights will take off on Mondays, Tuesdays, Fridays and Sundays.