DL 8839 then UA 3706 at Detroit
Philadelphia → Detroit → Newark
Timetable, Detroit time
02:33DL 8839 from Philadelphia at the gate
11:35UA 3706 to Newark leaves the gate
9 h 02 apart on the timetable
The last days
DL 8839 and UA 3706 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.