AA 9909 then UA 1349 at O'Hare
Waterloo → Chicago → Pittsburgh
Timetable, Chicago time
17:10AA 9909 from Waterloo at the gate
14:16UA 1349 to Pittsburgh leaves the gate
21 h 06 apart on the timetable, overnight
UA 1349 leaves 21 h 06 after AA 9909 arrives on the timetable: more than half a day, so not a connection we count.