UA 3501 then UA 2811 at O'Hare
Kansas City → Chicago → Las Vegas
Timetable, Chicago time
17:05UA 3501 from Kansas City at the gate
09:00UA 2811 to Las Vegas leaves the gate
15 h 55 apart on the timetable, overnight
UA 2811 leaves 15 h 55 after UA 3501 arrives on the timetable: more than half a day, so not a connection we count.