AA 6468 then UA 5191 at O'Hare
St Louis → Chicago → Lancaster
Timetable, Chicago time
15:03AA 6468 from St Louis at the gate
08:50UA 5191 to Lancaster leaves the gate
17 h 47 apart on the timetable, overnight
UA 5191 leaves 17 h 47 after AA 6468 arrives on the timetable: more than half a day, so not a connection we count.