AA 3077 then UA 3874 at O'Hare
Las Vegas → Chicago → LCQ
Timetable, Chicago time
11:52AA 3077 from Las Vegas at the gate
06:30UA 3874 to LCQ leaves the gate
18 h 38 apart on the timetable, overnight
UA 3874 leaves 18 h 38 after AA 3077 arrives on the timetable: more than half a day, so not a connection we count.