DL 278 then WN 261 at Atlanta
Buenos Aires → Atlanta → Denver
Timetable, Atlanta time
07:44DL 278 from Buenos Aires at the gate
17:35WN 261 to Denver leaves the gate
9 h 51 apart on the timetable
The last days
DL 278 and WN 261 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.