AA 1854 then UA 3876 at O'Hare
San Francisco → Chicago → Miami
Timetable, Chicago time
05:59AA 1854 from San Francisco at the gate
21:00UA 3876 to Miami leaves the gate
15 h 01 apart on the timetable
UA 3876 leaves 15 h 01 after AA 1854 arrives on the timetable: more than half a day, so not a connection we count.