UA 4980 then UA 3754 at Houston
Harlingen → Houston → Waco
Timetable, Houston time
15:26UA 4980 from Harlingen at the gate
11:30UA 3754 to Waco leaves the gate
20 h 04 apart on the timetable, overnight
UA 3754 leaves 20 h 04 after UA 4980 arrives on the timetable: more than half a day, so not a connection we count.