DL 9936 then DL 727 at Atlanta
ILN → Atlanta → Washington National
Timetable, Atlanta time
15:29DL 9936 from ILN at the gate
19:59DL 727 to Washington National leaves the gate
4 h 30 apart on the timetable
The last days
DL 9936 and DL 727 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.