AA 1225 then UA 375 at Boston
Miami → Boston → Chicago O'Hare
Timetable, Boston time
13:55AA 1225 from Miami at the gate
13:29UA 375 to Chicago O'Hare leaves the gate
23 h 34 apart on the timetable, overnight
UA 375 leaves 23 h 34 after AA 1225 arrives on the timetable: more than half a day, so not a connection we count.