AA 6366 then UA 3911 at O'Hare
Waterloo → Chicago → Savannah
Timetable, Chicago time
07:39AA 6366 from Waterloo at the gate
05:30UA 3911 to Savannah leaves the gate
21 h 51 apart on the timetable, overnight
UA 3911 leaves 21 h 51 after AA 6366 arrives on the timetable: more than half a day, so not a connection we count.