F9 2399 then UA 3917 at Houston
Atlanta → Houston → Austin
Timetable, Houston time
11:34F9 2399 from Atlanta at the gate
07:30UA 3917 to Austin leaves the gate
19 h 56 apart on the timetable, overnight
UA 3917 leaves 19 h 56 after F9 2399 arrives on the timetable: more than half a day, so not a connection we count.