UA 3922 then DL 1655 at San Francisco
Denver → San Francisco → Boston
Timetable, San Francisco time
20:45UA 3922 from Denver at the gate
21:58DL 1655 to Boston leaves the gatealso VS 2642, LA 6808
1 h 13 apart on the timetable
The last days
UA 3922 and DL 1655 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.