UA 3758 then UA 2406 at Houston
Fort Worth → Houston → Las Vegas
Timetable, Houston time
18:41UA 3758 from Fort Worth at the gate
18:40UA 2406 to Las Vegas leaves the gate
23 h 59 apart on the timetable, overnight
UA 2406 leaves 23 h 59 after UA 3758 arrives on the timetable: more than half a day, so not a connection we count.