DL 503 then DL 2738 at Atlanta
Detroit → Atlanta → Chicago O'Hare
Timetable, Atlanta time
11:27DL 503 from Detroit at the gate
15:50DL 2738 to Chicago O'Hare leaves the gate
4 h 23 apart on the timetable
The last days
DL 503 and DL 2738 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.