OO 9909 then UA 455 at O'Hare
Waterloo → Chicago → Phoenix
Timetable, Chicago time
16:47OO 9909 from Waterloo at the gate
12:55UA 455 to Phoenix leaves the gate
20 h 08 apart on the timetable, overnight
UA 455 leaves 20 h 08 after OO 9909 arrives on the timetable: more than half a day, so not a connection we count.