AA 9928 then UA 278 at O'Hare
New York LaGuardia → Chicago → Atlanta
Timetable, Chicago time
06:45AA 9928 from New York LaGuardia at the gate
20:03UA 278 to Atlanta leaves the gate
13 h 18 apart on the timetable
UA 278 leaves 13 h 18 after AA 9928 arrives on the timetable: more than half a day, so not a connection we count.