This has been asked before, and answered well by /u/kieslowskifan here. The German Kriegsmarine had been pushing for carriers to be added to their fleet. Their 1938 Z Plan, to be completed by 1948, was to include 8 carriers, along a strong fleet of battleships and pocket-battleships. In 1936, work started on the first German carrier, the Graf Zeppelin. She would be launched in 1938, but work on her hadn't finished by September 1939. The war caused several delays, and equipment meant for her was diverted to other uses - her 150mm guns were instead emplaced in Norway for coastal defence, while their fire control was traded to the USSR. In 1943, following the failure of the German surface fleet to destroy an Allied convoy in the Battle of the Barents Sea, construction on her was completely cancelled. Her hulk was captured by the USSR in 1945, and sunk as a target ship. She was not a good design, with a heavy anti-surface armament (and a near-permanent list). This was compounded by a lack of experience with carrier operations within the Kriegsmarine. Kriegsmarine planners had no idea of the best ways to use a carrier, while they had no aircrews experienced with the limitations of carrier aviation. Compounding this, inter-service rivalry between the Kriegsmarine and the Luftwaffe would have made her more useless - the Luftwaffe wanted control of all aircraft in Nazi Germany, and didn't want to support carrier aviation.