AA 3575 then UA 3876 at O'Hare
Springfield Branson National → Chicago → Miami
Timetable, Chicago time
15:30AA 3575 from Springfield Branson National at the gate
07:00UA 3876 to Miami leaves the gate
15 h 30 apart on the timetable, overnight
UA 3876 leaves 15 h 30 after AA 3575 arrives on the timetable: more than half a day, so not a connection we count.