UA 2153 then CA 3104 at O'Hare
Richmond → Chicago → Shanghai
Timetable, Chicago time
07:42UA 2153 from Richmond at the gate
11:40CA 3104 to Shanghai leaves the gate
3 h 58 apart on the timetable
The last days
UA 2153 and CA 3104 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.