AA 640 then UA 504 at Denver
Charlotte → Denver → San Francisco
Timetable, Denver time
13:27AA 640 from Charlotte at the gate
16:34UA 504 to San Francisco leaves the gate
3 h 07 apart on the timetable
The last days
AA 640 and UA 504 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.