OO 9909 then UA 321 at O'Hare
Waterloo → Chicago → Phoenix
Timetable, Chicago time
16:47OO 9909 from Waterloo at the gate
09:15UA 321 to Phoenix leaves the gate
16 h 28 apart on the timetable, overnight
UA 321 leaves 16 h 28 after OO 9909 arrives on the timetable: more than half a day, so not a connection we count.