AA 3071 then UA 3757 at Dulles
Los Angeles → Washington → Buffalo
Timetable, Washington time
04:35AA 3071 from Los Angeles at the gate
17:00UA 3757 to Buffalo leaves the gate
12 h 25 apart on the timetable
UA 3757 leaves 12 h 25 after AA 3071 arrives on the timetable: more than half a day, so not a connection we count.