UA 1936 then AA 2253 at San Francisco
Eugene → San Francisco → Chicago O'Hare
Timetable, San Francisco time
21:05UA 1936 from Eugene at the gatealso OZ 6325
17:27AA 2253 to Chicago O'Hare leaves the gatealso QF 4756
20 h 22 apart on the timetable, overnight
AA 2253 leaves 20 h 22 after UA 1936 arrives on the timetable: more than half a day, so not a connection we count.