DL 5614 then AA 2578 at Boston
Milwaukee → Boston → Chicago O'Hare
Timetable, Boston time
17:53DL 5614 from Milwaukee at the gate
15:31AA 2578 to Chicago O'Hare leaves the gate
21 h 38 apart on the timetable, overnight
AA 2578 leaves 21 h 38 after DL 5614 arrives on the timetable: more than half a day, so not a connection we count.