AA 9908 then UA 1580 at O'Hare
Milwaukee → Chicago → Boston
Timetable, Chicago time
13:50AA 9908 from Milwaukee at the gate
12:46UA 1580 to Boston leaves the gate
22 h 56 apart on the timetable, overnight
UA 1580 leaves 22 h 56 after AA 9908 arrives on the timetable: more than half a day, so not a connection we count.