DL 1019 then DL 916 at Detroit
Boston → Detroit → Las Vegas
Timetable, Detroit time
07:50DL 1019 from Boston at the gate
20:05DL 916 to Las Vegas leaves the gate
12 h 15 apart on the timetable
DL 916 leaves 12 h 15 after DL 1019 arrives on the timetable: more than half a day, so not a connection we count.