AA 2771 then UA 3874 at O'Hare
Denver → Chicago → LCQ
Timetable, Chicago time
10:30AA 2771 from Denver at the gate
06:30UA 3874 to LCQ leaves the gate
20 h apart on the timetable, overnight
UA 3874 leaves 20 h after AA 2771 arrives on the timetable: more than half a day, so not a connection we count.