Finding disguised seaplane scouts without exposing Enigma

A disguised seaplane carrier would complicate the use of Enigma intelligence against German wolf packs. British forces would need a plausible reason to find it, such as a patrol-aircraft encounter, without revealing that they already knew where to search. A ship answering signals normally and showing no suspicious activity could move before a signalling discrepancy was resolved. Repeated successful interceptions would therefore need a convincing search routine. Airborne scouts would also make it harder to divert convoys around submarine concentrations while leaving the Germans to attribute missed contacts to small errors in estimated course.