DL 278 then DL 2990 at Atlanta
Buenos Aires → Atlanta → Jacksonville
Timetable, Atlanta time
07:44DL 278 from Buenos Aires at the gate
13:46DL 2990 to Jacksonville leaves the gate
6 h 02 apart on the timetable
The last days
DL 278 and DL 2990 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.