AA 9950 then UA 3575 at O'Hare
Philadelphia → Chicago → Montréal
Timetable, Chicago time
13:49AA 9950 from Philadelphia at the gate
10:37UA 3575 to Montréal leaves the gate
20 h 48 apart on the timetable, overnight
UA 3575 leaves 20 h 48 after AA 9950 arrives on the timetable: more than half a day, so not a connection we count.