AA 2103 then AA 3916 at DFW
St Louis → Dallas-Fort Worth → Monterrey
Timetable, Dallas-Fort Worth time
09:33AA 2103 from St Louis at the gate
21:56AA 3916 to Monterrey leaves the gate
12 h 23 apart on the timetable
AA 3916 leaves 12 h 23 after AA 2103 arrives on the timetable: more than half a day, so not a connection we count.