UA 4381 then BR 643 at O'Hare
Buffalo → Chicago → Anchorage
Timetable, Chicago time
14:55UA 4381 from Buffalo at the gate
14:50BR 643 to Anchorage leaves the gate
23 h 55 apart on the timetable, overnight
BR 643 leaves 23 h 55 after UA 4381 arrives on the timetable: more than half a day, so not a connection we count.