AA 2537 then CA 1018 at O'Hare
Tucson → Chicago → Shanghai
Timetable, Chicago time
20:15AA 2537 from Tucson at the gate
03:00CA 1018 to Shanghai leaves the gate
6 h 45 apart on the timetable, overnight
The last days
AA 2537 and CA 1018 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.