UA 6251 then UA 451 at Houston
Detroit → Houston → Boston
Timetable, Houston time
13:21UA 6251 from Detroit at the gate
14:20UA 451 to Boston leaves the gate
59 min apart on the timetable
The last days
UA 6251 and UA 451 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.