AA 9782 then CZ 2502 at O'Hare
Boston → Chicago → Shanghai
Timetable, Chicago time
13:14AA 9782 from Boston at the gate
13:55CZ 2502 to Shanghai leaves the gate
41 min apart on the timetable
The last days
AA 9782 and CZ 2502 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.