AA 2644 then 5X 603 at O'Hare
Pittsburgh → Chicago → Louisville
Timetable, Chicago time
09:05AA 2644 from Pittsburgh at the gate
21:235X 603 to Louisville leaves the gate
12 h 18 apart on the timetable
5X 603 leaves 12 h 18 after AA 2644 arrives on the timetable: more than half a day, so not a connection we count.