AA 4479 then UA 5191 at O'Hare
Pittsburgh → Chicago → Lancaster
Timetable, Chicago time
14:00AA 4479 from Pittsburgh at the gate
08:50UA 5191 to Lancaster leaves the gate
18 h 50 apart on the timetable, overnight
UA 5191 leaves 18 h 50 after AA 4479 arrives on the timetable: more than half a day, so not a connection we count.