AA 2230 then UA 2621 at Houston
Miami → Houston → Austin
Timetable, Houston time
23:58AA 2230 from Miami at the gate
20:25UA 2621 to Austin leaves the gate
20 h 27 apart on the timetable, overnight
UA 2621 leaves 20 h 27 after AA 2230 arrives on the timetable: more than half a day, so not a connection we count.