United Airlines (UA, Chicago O'Hare) has again deferred the launch of its planned second daily rotation between San Francisco and Shanghai Pudong owing to a scarcity of suitable landing and take-off slots in the Chinese metropolis.

According to Airline Route, the carrier had planned to launch the flight on May 16 only to delay that date until July 2. However, schedule data now reveals the flight has been postponed until further notice.

United already operates a daily B747-400 service on the route.