AA 3687 then AA 1408 at DFW
Montrose → Dallas-Fort Worth → Huatulco
Timetable, Dallas-Fort Worth time
16:22AA 3687 from Montrose at the gate
10:49AA 1408 to Huatulco leaves the gate
18 h 27 apart on the timetable, overnight
AA 1408 leaves 18 h 27 after AA 3687 arrives on the timetable: more than half a day, so not a connection we count.