F9 2428 then DL 1491 at Atlanta
Las Vegas → Atlanta → Austin
Timetable, Atlanta time
04:49F9 2428 from Las Vegas at the gate
16:55DL 1491 to Austin leaves the gate
12 h 06 apart on the timetable
DL 1491 leaves 12 h 06 after F9 2428 arrives on the timetable: more than half a day, so not a connection we count.