AA 9950 then UA 2811 at O'Hare
Philadelphia → Chicago → Las Vegas
Timetable, Chicago time
13:49AA 9950 from Philadelphia at the gate
09:00UA 2811 to Las Vegas leaves the gate
19 h 11 apart on the timetable, overnight
UA 2811 leaves 19 h 11 after AA 9950 arrives on the timetable: more than half a day, so not a connection we count.