AM 686 then UA 3907 at O'Hare
Mexico City → Chicago → Cleveland
Timetable, Chicago time
13:12AM 686 from Mexico City at the gate
07:30UA 3907 to Cleveland leaves the gate
18 h 18 apart on the timetable, overnight
UA 3907 leaves 18 h 18 after AM 686 arrives on the timetable: more than half a day, so not a connection we count.