UA 4345 then UA 3439 at Detroit
Washington → Detroit → Newark
Timetable, Detroit time
10:19UA 4345 from Washington at the gate
17:12UA 3439 to Newark leaves the gate
6 h 53 apart on the timetable
The last days
UA 4345 and UA 3439 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.