AA 2120 then UA 3912 at San Francisco
Dallas-Fort Worth → San Francisco → Houston
Timetable, San Francisco time
08:56AA 2120 from Dallas-Fort Worth at the gatealso IB 8018
23:00UA 3912 to Houston leaves the gate
14 h 04 apart on the timetable
UA 3912 leaves 14 h 04 after AA 2120 arrives on the timetable: more than half a day, so not a connection we count.