AA 946 then UA 1510 at Denver
Philadelphia → Denver → San Francisco
Timetable, Denver time
13:59AA 946 from Philadelphia at the gate
17:25UA 1510 to San Francisco leaves the gate
3 h 26 apart on the timetable
The last days
AA 946 and UA 1510 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.