CZ 660 then CA 3509 at Guangzhou
San Francisco → Guangzhou → Xi'an
Timetable, Guangzhou time
10:25CZ 660 from San Francisco at the gate
21:05CA 3509 to Xi'an leaves the gatealso G5 6071, TV 6527, KY 9161, SC 9191
10 h 40 apart on the timetable
The last days
CZ 660 and CA 3509 weren’t both flown 15 min to 12 h apart in the last 21 days.
Statistics from past flights, not live flight information. Always check times and your connection with your airline, and don’t base travel or booking decisions on these numbers.