DL 169 then DL 2896 at Boston
Barcelona → Boston → Detroit
Timetable, Boston time
13:41DL 169 from Barcelona at the gate
20:05DL 2896 to Detroit leaves the gate
6 h 24 apart on the timetable
The last days
DL 169 and DL 2896 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.