UA 3905 then AA 2551 at Houston
Cancún → Houston → Dallas-Fort Worth
Timetable, Houston time
13:29UA 3905 from Cancún at the gate
06:00AA 2551 to Dallas-Fort Worth leaves the gate
16 h 31 apart on the timetable, overnight
AA 2551 leaves 16 h 31 after UA 3905 arrives on the timetable: more than half a day, so not a connection we count.