AA 5391 then UA 3875 at Houston
Washington National → Houston → Melbourne (Florida)
Timetable, Houston time
22:18AA 5391 from Washington National at the gate
22:00UA 3875 to Melbourne (Florida) leaves the gate
23 h 42 apart on the timetable, overnight
UA 3875 leaves 23 h 42 after AA 5391 arrives on the timetable: more than half a day, so not a connection we count.