Among the flights of the air carrier described as American Airlines, what is the percentage of the flights with earlier departure?
American Airlines can be found in Description which contains 'American Airlines'; percentage = MULTIPLY(DIVIDE(SUM(DEP_DELAY < 0), COUNT(DEP_DELAY)), 1.0); earlier departure refers to DEP_DELAY < 0;
SELECT CAST(SUM(CASE WHEN T2.DEP_DELAY < 0 THEN 1 ELSE 0 END) AS REAL) * 100 / COUNT(*) FROM `Air Carriers` AS T1 INNER JOIN Airlines AS T2 ON T1.Code = T2.OP_CARRIER_AIRLINE_ID WHERE T1.Description LIKE '%American Airlines%'
CREATE TABLE IF NOT EXISTS "Air Carriers"
(
    Code        INTEGER
            primary key,
    Description TEXT
);
CREATE TABLE Airports
(
    Code        TEXT
            primary key,
    Description TEXT
);
CREATE TABLE Airlines
(
    FL_DATE               TEXT,
    OP_CARRIER_AIRLINE_ID INTEGER,
    TAIL_NUM              TEXT,
    OP_CARRIER_FL_NUM     INTEGER,
    ORIGIN_AIRPORT_ID     INTEGER,
    ORIGIN_AIRPORT_SEQ_ID INTEGER,
    ORIGIN_CITY_MARKET_ID INTEGER,
    ORIGIN                TEXT,
    DEST_AIRPORT_ID       INTEGER,
    DEST_AIRPORT_SEQ_ID   INTEGER,
    DEST_CITY_MARKET_ID   INTEGER,
    DEST                  TEXT,
    CRS_DEP_TIME          INTEGER,
    DEP_TIME              INTEGER,
    DEP_DELAY             INTEGER,
    DEP_DELAY_NEW         INTEGER,
    ARR_TIME              INTEGER,
    ARR_DELAY             INTEGER,
    ARR_DELAY_NEW         INTEGER,
    CANCELLED             INTEGER,
    CANCELLATION_CODE     TEXT,
    CRS_ELAPSED_TIME      INTEGER,
    ACTUAL_ELAPSED_TIME   INTEGER,
    CARRIER_DELAY         INTEGER,
    WEATHER_DELAY         INTEGER,
    NAS_DELAY             INTEGER,
    SECURITY_DELAY        INTEGER,
    LATE_AIRCRAFT_DELAY   INTEGER,
    FOREIGN KEY (ORIGIN) REFERENCES Airports(Code),
    FOREIGN KEY (DEST) REFERENCES Airports(Code),
    FOREIGN KEY (OP_CARRIER_AIRLINE_ID) REFERENCES "Air Carriers"(Code)
);
