UA 3909 then AA 797 at O'Hare
Newark → Chicago → Boston
Timetable, Chicago time
11:38UA 3909 from Newark at the gate
15:16AA 797 to Boston leaves the gate
3 h 38 apart on the timetable
The last days
UA 3909 and AA 797 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.