AA 6345 then UA 3874 at O'Hare
Lexington → Chicago → LCQ
Timetable, Chicago time
11:59AA 6345 from Lexington at the gate
06:30UA 3874 to LCQ leaves the gate
18 h 31 apart on the timetable, overnight
UA 3874 leaves 18 h 31 after AA 6345 arrives on the timetable: more than half a day, so not a connection we count.