DL 901 then DL 1889 at Atlanta
Phoenix → Atlanta → Boston
Timetable, Atlanta time
12:47DL 901 from Phoenix at the gate
19:20DL 1889 to Boston leaves the gate
6 h 33 apart on the timetable
The last days
DL 901 and DL 1889 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.