AA 990 then UA 3872 at O'Hare
Phoenix → Chicago → LCQ
Timetable, Chicago time
11:39AA 990 from Phoenix at the gate
00:31UA 3872 to LCQ leaves the gate
12 h 52 apart on the timetable, overnight
UA 3872 leaves 12 h 52 after AA 990 arrives on the timetable: more than half a day, so not a connection we count.