AC 1721 then DL 843 at Phoenix
Toronto → Phoenix → San Diego
Timetable, Phoenix time
12:47AC 1721 from Toronto at the gate
16:35DL 843 to San Diego leaves the gate
3 h 48 apart on the timetable
The last days
AC 1721 and DL 843 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.