AA 4257 then AA 3351 at DFW
Amarillo → Dallas-Fort Worth → Houston Hobby
Timetable, Dallas-Fort Worth time
06:20AA 4257 from Amarillo at the gate
18:23AA 3351 to Houston Hobby leaves the gate
12 h 03 apart on the timetable
AA 3351 leaves 12 h 03 after AA 4257 arrives on the timetable: more than half a day, so not a connection we count.