G7 3375 then UA 5380 at O'Hare
St Louis → Chicago → Flint
Timetable, Chicago time
08:23G7 3375 from St Louis at the gate
21:20UA 5380 to Flint leaves the gate
12 h 57 apart on the timetable
UA 5380 leaves 12 h 57 after G7 3375 arrives on the timetable: more than half a day, so not a connection we count.