K4 579 then UA 1580 at O'Hare
Fairbanks → Chicago → Boston
Timetable, Chicago time
16:23K4 579 from Fairbanks at the gate
12:46UA 1580 to Boston leaves the gate
20 h 23 apart on the timetable, overnight
UA 1580 leaves 20 h 23 after K4 579 arrives on the timetable: more than half a day, so not a connection we count.