Question: How many flights from Charlotte Douglas International Airport to Austin - Bergstrom International Airport experienced serious reasons that cause flight cancellation?
SQL: SELECT COUNT(*) FROM Airlines AS T1 INNER JOIN Airports AS T2 ON T1.ORIGIN = T2.Code WHERE T1.ORIGIN = 'CLT' AND T1.DEST = 'AUS' AND T2.Description = 'Charlotte, NC: Charlotte Douglas International' AND T1.CANCELLATION_CODE = 'A'