UA 2809 then AA 3484 at O'Hare
Fort Lauderdale → Chicago → St Louis
Timetable, Chicago time
09:31UA 2809 from Fort Lauderdale at the gate
09:30AA 3484 to St Louis leaves the gate
23 h 59 apart on the timetable, overnight
AA 3484 leaves 23 h 59 after UA 2809 arrives on the timetable: more than half a day, so not a connection we count.