AA 1200 then UA 3874 at O'Hare
Washington National → Chicago → LCQ
Timetable, Chicago time
11:34AA 1200 from Washington National at the gate
06:30UA 3874 to LCQ leaves the gate
18 h 56 apart on the timetable, overnight
UA 3874 leaves 18 h 56 after AA 1200 arrives on the timetable: more than half a day, so not a connection we count.