DL 1843 then AA 9912 at O'Hare
Boston → Chicago → Richmond
Timetable, Chicago time
09:48DL 1843 from Boston at the gate
07:30AA 9912 to Richmond leaves the gate
21 h 42 apart on the timetable, overnight
AA 9912 leaves 21 h 42 after DL 1843 arrives on the timetable: more than half a day, so not a connection we count.