WN 855 then UA 779 at Denver
Dallas → Denver → Boston
Timetable, Denver time
07:10WN 855 from Dallas at the gate
15:56UA 779 to Boston leaves the gate
8 h 46 apart on the timetable
The last days
WN 855 and UA 779 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.