DL 9936 then DL 821 at Atlanta
ILN → Atlanta → Boston
Timetable, Atlanta time
15:29DL 9936 from ILN at the gate
17:50DL 821 to Boston leaves the gate
2 h 21 apart on the timetable
The last days
DL 9936 and DL 821 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.