AA 2278 then CZ 2502 at O'Hare
Puerto Vallarta → Chicago → Shanghai
Timetable, Chicago time
21:00AA 2278 from Puerto Vallarta at the gate
01:45CZ 2502 to Shanghai leaves the gate
4 h 45 apart on the timetable, overnight
The last days
AA 2278 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.