DL 8839 then DL 3831 at Phoenix
Calgary → Phoenix → Austin
Timetable, Phoenix time
09:55DL 8839 from Calgary at the gate
10:40DL 3831 to Austin leaves the gate
45 min apart on the timetable
The last days
DL 8839 and DL 3831 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.