AA 9866 then H2 4920 at O'Hare
Marquette → Chicago → Milwaukee
Timetable, Chicago time
10:30AA 9866 from Marquette at the gate
13:33H2 4920 to Milwaukee leaves the gate
3 h 03 apart on the timetable
The last days
AA 9866 and H2 4920 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.