AA 3258 then DL 954 at Houston
Miami → Houston → Detroit
Timetable, Houston time
09:00AA 3258 from Miami at the gate
15:35DL 954 to Detroit leaves the gate
6 h 35 apart on the timetable
The last days
AA 3258 and DL 954 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.