OO 9909 then AA 1475 at O'Hare
Waterloo → Chicago → Las Vegas
Timetable, Chicago time
16:47OO 9909 from Waterloo at the gate
13:52AA 1475 to Las Vegas leaves the gate
21 h 05 apart on the timetable, overnight
AA 1475 leaves 21 h 05 after OO 9909 arrives on the timetable: more than half a day, so not a connection we count.