UA 3902 then UA 2811 at O'Hare
Rio De Janeiro → Chicago → Las Vegas
Timetable, Chicago time
17:01UA 3902 from Rio De Janeiro at the gate
09:00UA 2811 to Las Vegas leaves the gate
15 h 59 apart on the timetable, overnight
UA 2811 leaves 15 h 59 after UA 3902 arrives on the timetable: more than half a day, so not a connection we count.