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_26134 ( "Type of unit" text, "Type of aircraft" text, "Number of aircraft" text, "Number of crews" text, "Men per crew" text, "Total personnel" real, "Officers" real, "Enlisted" real )

### Question ###
What is the aircraft for 21 crews?

### Accurate SQL ###

SELECT "Type of aircraft" FROM table_26134 WHERE "Number of crews" = '21'