UA 3878 then AC 580 at Houston
IAB → Houston → Montréal
Timetable, Houston time
22:40UA 3878 from IAB at the gate
11:50AC 580 to Montréal leaves the gate
13 h 10 apart on the timetable, overnight
AC 580 leaves 13 h 10 after UA 3878 arrives on the timetable: more than half a day, so not a connection we count.