AA 3731 then UA 3376 at O'Hare
Greenville-Spartanburg → Chicago → St Louis
Timetable, Chicago time
18:01AA 3731 from Greenville-Spartanburg at the gate
11:00UA 3376 to St Louis leaves the gate
16 h 59 apart on the timetable, overnight
UA 3376 leaves 16 h 59 after AA 3731 arrives on the timetable: more than half a day, so not a connection we count.