AA 9921 then CA 1012 at O'Hare
Phoenix → Chicago → Shanghai
Timetable, Chicago time
16:00AA 9921 from Phoenix at the gate
19:50CA 1012 to Shanghai leaves the gate
3 h 50 apart on the timetable
The last days
AA 9921 and CA 1012 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.