UA 647 then AA 1366 at Denver
Durango → Denver → Chicago O'Hare
Timetable, Denver time
08:24UA 647 from Durango at the gate
14:27AA 1366 to Chicago O'Hare leaves the gate
6 h 03 apart on the timetable
The last days
UA 647 and AA 1366 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.