user: Question: What was the aircraft flown when the axis unit was Luftwaffe (**) and the enemy aircraft was Ju.88?
Columns: ['Date (dd.mm.yyyy)', 'Soviet Unit', 'Aircraft flown', 'Enemy Aircraft', 'Axis Unit']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['13.09.1942', '437 IAP', 'Yak-1 "White 02"', 'Ju.88', 'Luftwaffe (**)']
SQL:

assistant: SELECT "Aircraft flown" FROM "Table" WHERE "Axis Unit" = 'Luftwaffe (**)' AND "Enemy Aircraft" = 'Ju.88';