AA 506 then UA 3907 at O'Hare
Charlotte → Chicago → Washington
Timetable, Chicago time
14:30AA 506 from Charlotte at the gate
12:00UA 3907 to Washington leaves the gate
21 h 30 apart on the timetable, overnight
UA 3907 leaves 21 h 30 after AA 506 arrives on the timetable: more than half a day, so not a connection we count.