How many flights on average does American Airlines Inc. operate every day in August, 2018?
flights on average = DIVIDE(COUNT(Code), 31); American Airlines Inc. refers to Description = 'American Airlines Inc.: AA'; every day in August, 2018 refers to FL_DATE like '2018/8%';
SELECT CAST( SUM(CASE WHEN T2.FL_DATE LIKE '2018/8%' THEN 1 ELSE 0 END) AS REAL) / 31 FROM Airports AS T1 INNER JOIN Airlines AS T2 ON T1.Code = T2.ORIGIN INNER JOIN `Air Carriers` AS T3 ON T2.OP_CARRIER_AIRLINE_ID = T3.Code WHERE T3.Description = 'American Airlines Inc.: AA'