AS 315 then DL 3902 at Detroit
Seattle → Detroit → Chicago O'Hare
Timetable, Detroit time
05:40AS 315 from Seattle at the gate
10:10DL 3902 to Chicago O'Hare leaves the gate
4 h 30 apart on the timetable
The last days
AS 315 and DL 3902 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.