AA 3546 then DL 1297 at Boston
St Louis → Boston → Austin
Timetable, Boston time
13:44AA 3546 from St Louis at the gate
13:15DL 1297 to Austin leaves the gate
23 h 31 apart on the timetable, overnight
DL 1297 leaves 23 h 31 after AA 3546 arrives on the timetable: more than half a day, so not a connection we count.