UA 3913 then B6 2780 at Houston
Denver → Houston → Fort Lauderdale
Timetable, Houston time
21:22UA 3913 from Denver at the gate
12:45B6 2780 to Fort Lauderdale leaves the gate
15 h 23 apart on the timetable, overnight
B6 2780 leaves 15 h 23 after UA 3913 arrives on the timetable: more than half a day, so not a connection we count.