AA 643 then CZ 2502 at O'Hare
Los Angeles → Chicago → Shanghai
Timetable, Chicago time
18:00AA 643 from Los Angeles at the gate
01:45CZ 2502 to Shanghai leaves the gate
7 h 45 apart on the timetable, overnight
The last days
AA 643 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.