AA 686 then UA 3907 at San Francisco
Phoenix → San Francisco → Denver
Timetable, San Francisco time
22:37AA 686 from Phoenix at the gate
07:00UA 3907 to Denver leaves the gate
8 h 23 apart on the timetable, overnight
The last days
AA 686 and UA 3907 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.