B6 8359 then UA 3775 at Boston
New York JFK → Boston → Chicago O'Hare
Timetable, Boston time
08:32B6 8359 from New York JFK at the gate
12:30UA 3775 to Chicago O'Hare leaves the gate
3 h 58 apart on the timetable
The last days
B6 8359 and UA 3775 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.