AA 536 then UA 5539 at O'Hare
Charlotte → Chicago → Cleveland
Timetable, Chicago time
17:51AA 536 from Charlotte at the gate
10:45UA 5539 to Cleveland leaves the gate
16 h 54 apart on the timetable, overnight
UA 5539 leaves 16 h 54 after AA 536 arrives on the timetable: more than half a day, so not a connection we count.