How many flights from Charlotte Douglas International Airport to Austin - Bergstrom International Airport experienced serious reasons that cause flight cancellation?
from refers to ORIGIN; Charlotte Douglas International Airport refers to Description = 'Charlotte, NC: Charlotte Douglas International'; to refers to DEST; Austin - Bergstrom International Airport refers to Description = 'Austin, TX: Austin - Bergstrom International'; serious reasons refers to CANCELLATION_CODE = 'A';
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'