How many flights from American Airlines were cancelled due to a type A cancellation code?
American Airlines refers to Description = 'American Airlines Inc.: AA'; cancelled refers to Cancelled = 1; cancelled due to type A cancellation code refers to CANCELLATION_CODE = 'A';
SELECT COUNT(*) FROM Airlines AS T1 INNER JOIN `Air Carriers` AS T2 ON T1.OP_CARRIER_AIRLINE_ID = T2.Code WHERE T1.CANCELLATION_CODE = 'A' AND T2.Description = 'American Airlines Inc.: AA' AND T1.CANCELLED = 1