UA 2045 then UA 2004 at Denver
Miami → Denver → Chicago O'Hare
Timetable, Denver time
10:04UA 2045 from Miami at the gate
15:14UA 2004 to Chicago O'Hare leaves the gate
5 h 10 apart on the timetable
The last days
UA 2045 and UA 2004 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.