F9 1572 then UA 3757 at Phoenix
San Diego → Phoenix → Denver
Timetable, Phoenix time
13:41F9 1572 from San Diego at the gate
17:27UA 3757 to Denver leaves the gate
3 h 46 apart on the timetable
The last days
F9 1572 and UA 3757 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.