UA 3905 then UA 4261 at Houston
Cancún → Houston → Lubbock
Timetable, Houston time
13:29UA 3905 from Cancún at the gate
09:30UA 4261 to Lubbock leaves the gate
20 h 01 apart on the timetable, overnight
UA 4261 leaves 20 h 01 after UA 3905 arrives on the timetable: more than half a day, so not a connection we count.