DL 973 then DL 834 at Atlanta
Boston → Atlanta → Las Vegas
Timetable, Atlanta time
21:59DL 973 from Boston at the gate
21:52DL 834 to Las Vegas leaves the gate
23 h 53 apart on the timetable, overnight
DL 834 leaves 23 h 53 after DL 973 arrives on the timetable: more than half a day, so not a connection we count.