AA 557 then DL 8771 at Atlanta
Philadelphia → Atlanta → Detroit
Timetable, Atlanta time
18:09AA 557 from Philadelphia at the gate
21:35DL 8771 to Detroit leaves the gate
3 h 26 apart on the timetable
The last days
AA 557 and DL 8771 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.