AA 639 then DL 2128 at Atlanta
Chicago O'Hare → Atlanta → Denver
Timetable, Atlanta time
09:59AA 639 from Chicago O'Hare at the gate
10:40DL 2128 to Denver leaves the gate
41 min apart on the timetable
The last days
AA 639 and DL 2128 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.