UA 5814 then AA 4547 at O'Hare
Detroit → Chicago → Boston
Timetable, Chicago time
06:57UA 5814 from Detroit at the gate
10:54AA 4547 to Boston leaves the gate
3 h 57 apart on the timetable
The last days
UA 5814 and AA 4547 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.