The Japanese navy conducted 4 reconnaissance overflights of Sydney during WWII. Of those, three were in the period leading up to the mini sub attack on Sydney Harbour. A last overflight was held the better part of a year later. Of these four flights, two went unnoticed, one was noticed, but the battery was told not to engage the aircraft as it was thought to be an American plane. In the last overflight (many months after the minisub raid), the Georges Head battery fired 4 shots at the plane.
All of the planes returned to their launching sub to report their intelligence.