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_name_40 (aircraft_flown VARCHAR, axis_unit VARCHAR, enemy_aircraft VARCHAR)

### Question ###
What was the aircraft flown when the axis unit was luftwaffe (**) and the enemy aircraft was ju.88?

### Accurate SQL ###

SELECT aircraft_flown FROM table_name_40 WHERE axis_unit = "luftwaffe (**)" AND enemy_aircraft = "ju.88"