UA 12 then FX 9791 at O'Hare
Zurich → Chicago → Anchorage
Timetable, Chicago time
12:40UA 12 from Zurich at the gate
04:00FX 9791 to Anchorage leaves the gate
15 h 20 apart on the timetable, overnight
FX 9791 leaves 15 h 20 after UA 12 arrives on the timetable: more than half a day, so not a connection we count.