Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_1291 ( "Airline" text, "ICAO" text, "IATA" text, "Callsign" text, "Commenced operations" real, "Fleet size" real, "Headquarters" text )

### Question ###
How large is the fleet size of the airline with the IATA code of 5j?

### Accurate SQL ###

SELECT COUNT("Fleet size") FROM table_1291 WHERE "IATA" = '5J'