AA 1652 then UA 3636 at O'Hare
Philadelphia → Chicago → Knoxville
Timetable, Chicago time
07:27AA 1652 from Philadelphia at the gate
07:07UA 3636 to Knoxville leaves the gate
23 h 40 apart on the timetable, overnight
UA 3636 leaves 23 h 40 after AA 1652 arrives on the timetable: more than half a day, so not a connection we count.