Mike,

At the moment, the UC 66 is the only confirmed sinking. One more reattribution to an air attack is likely soon -- I just need to pry the location of a wreck from a diver. A third is possible, subject to the details of a different wreck.

The RN did attribute some additional U-boat losses to air attack in World War I but their staff work left much to be desired. Many Flanders-based U-boats that went missing we now know were lost on British mines between Zeebrugge and the Straits of Dover.

Best wishes,
Michael