AA 9950 then UA 3487 at O'Hare
Philadelphia → Chicago → Key West
Timetable, Chicago time
13:49AA 9950 from Philadelphia at the gate
11:00UA 3487 to Key West leaves the gate
21 h 11 apart on the timetable, overnight
UA 3487 leaves 21 h 11 after AA 9950 arrives on the timetable: more than half a day, so not a connection we count.