UA 2656 then DL 139 at Boston
Denver → Boston → New York JFK
Timetable, Boston time
05:52UA 2656 from Denver at the gate
14:30DL 139 to New York JFK leaves the gatealso DL 169
8 h 38 apart on the timetable
The last days
UA 2656 and DL 139 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.