AA 2878 then WN 1817 at Denver
Philadelphia → Denver → San Francisco
Timetable, Denver time
18:35AA 2878 from Philadelphia at the gate
19:45WN 1817 to San Francisco leaves the gate
1 h 10 apart on the timetable
The last days
AA 2878 and WN 1817 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.