UA 617 then LF 7920 at O'Hare
Denver → Chicago → BKX
Timetable, Chicago time
17:05UA 617 from Denver at the gate
13:45LF 7920 to BKX leaves the gate
20 h 40 apart on the timetable, overnight
LF 7920 leaves 20 h 40 after UA 617 arrives on the timetable: more than half a day, so not a connection we count.