AA 9975 then AA 1554 at Philadelphia
Roanoke → Philadelphia → Denver
Timetable, Philadelphia time
15:24AA 9975 from Roanoke at the gate
11:47AA 1554 to Denver leaves the gate
20 h 23 apart on the timetable, overnight
AA 1554 leaves 20 h 23 after AA 9975 arrives on the timetable: more than half a day, so not a connection we count.