AA 3040 then UA 1525 at O'Hare
Atlanta → Chicago → Las Vegas
Timetable, Chicago time
08:33AA 3040 from Atlanta at the gate
15:00UA 1525 to Las Vegas leaves the gate
6 h 27 apart on the timetable
The last days
AA 3040 and UA 1525 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.