UA 3920 then AA 1618 at Houston
Orlando → Houston → Phoenix
Timetable, Houston time
19:47UA 3920 from Orlando at the gate
14:38AA 1618 to Phoenix leaves the gate
18 h 51 apart on the timetable, overnight
AA 1618 leaves 18 h 51 after UA 3920 arrives on the timetable: more than half a day, so not a connection we count.