AA 808 then UA 3876 at O'Hare
Washington National → Chicago → Miami
Timetable, Chicago time
14:29AA 808 from Washington National at the gate
07:00UA 3876 to Miami leaves the gate
16 h 31 apart on the timetable, overnight
UA 3876 leaves 16 h 31 after AA 808 arrives on the timetable: more than half a day, so not a connection we count.