AA 6486 then UA 2220 at O'Hare
Detroit → Chicago → Boston
Timetable, Chicago time
17:29AA 6486 from Detroit at the gate
12:11UA 2220 to Boston leaves the gate
18 h 42 apart on the timetable, overnight
UA 2220 leaves 18 h 42 after AA 6486 arrives on the timetable: more than half a day, so not a connection we count.