Friendly Fire incidents, also called Blue on Blue attacks are a fairly common occurance in armed conflict. They occur on land, at sea and in the air. During WWII, B-17s and B-24 bombers flying in “box” formation to allow for mutual coverage of their .50 cal machine guns shot each other down as excited and target fixated gunners would rake one of their own bombers as they shot at a German fighter that passed near it. In France an air force bombing strike landed on US troops instead of the Germans when clouds covered the target and their navigation was off. At sea during the First Naval Battle of Guadalcanal, a close and confused fight in the dark with the Japanese Navy saw our Navy ships shooting at each other briefly resulting in the death of a US Admirals when the disabled light cruiser USS Atlanta drifted in front of the guns of the heavy cruiser USS San Francisco who mistook her for a Japanese warship.
There was a similar incident in the waters off France during WWII, when the German Luftwaffe and the German Kreigsmarine(navy) fought a furious battle with each other, not in the confusion of the night, but because of a series of bureaucratic snafu’s, organizational structure and faulty communications.
Within the vision Hitler had to rebuild the might of Germany was this: To build a Navy as badass as the Britain’s Royal Navy, but the treaty that ended WWII stood directly in the way. The Treaty of Versailles prohibited Germany from building submarines and they could only build a surface fleet of very limited size in terms of ships and their size. Germany decided to simply ignore it and embarked on a building program that saw the Kriegsmarine grow rapidly in through 1939 under a massive ship-building program called Plan Z. Under the plan, Germany would have a navy of 230 ships, including 13 battleships and battle cruisers, 4 aircraft carriers, 15 pocket battleships, 5 heavy cruisers, 13 light cruisers and 68 destroyers. Germany did not produce nearly enough oil to keep a fleet like this at sea so the plan itself made it obvious that Hitler and Germany would have to secure reliable sources of oil from somebody and that would probably involve conquest.
However, the program stopped when WWII broke out, and the Kriegsmarine was left out. If anything, Luftwaffe commander and Hitler’s second in command Hermann Göring was most to blame. He convinced Hitler that Germany could win the war with airpower and the Luftwaffe operating from shore would be enough to stop the Royal Navy. To make sure of this, he made sure that the Kreigsmarine would not have any aircraft to fly that it could call its own. Every coastal aircraft squadron and group asssigned to the Kreigsmarine was under the direct control of Goring and the Luftwaffe, even float planes on battleships like Bismark and Tirpitz, they were all flown by Lufwaffe pilots. If the German navy put to sea it would have to ask the Luftwaffe to provide air cover for them. The arrangement seemed to work okay until somthing called Operation Wikinger occured.