UA 5531 then UA 3754 at Houston
Oklahoma City → Houston → Waco
Timetable, Houston time
15:19UA 5531 from Oklahoma City at the gate
11:30UA 3754 to Waco leaves the gate
20 h 11 apart on the timetable, overnight
UA 3754 leaves 20 h 11 after UA 5531 arrives on the timetable: more than half a day, so not a connection we count.