UA 3756 then AA 4480 at O'Hare
Milwaukee → Chicago → Louisville
Timetable, Chicago time
14:07UA 3756 from Milwaukee at the gate
19:00AA 4480 to Louisville leaves the gate
4 h 53 apart on the timetable
The last days
UA 3756 and AA 4480 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.