AA 3111 then UA 1544 at O'Hare
St Louis → Chicago → Fort Myers
Timetable, Chicago time
13:00AA 3111 from St Louis at the gate
12:59UA 1544 to Fort Myers leaves the gate
23 h 59 apart on the timetable, overnight
UA 1544 leaves 23 h 59 after AA 3111 arrives on the timetable: more than half a day, so not a connection we count.