The Kriegsmarine's Plan Z blueprint for the German naval construction
program finalized in 1938, envisaged building 4 aircraft carriers,
but none were operational when war broke out. Also work was
started on 26 August 1942 on converting the Heavy cruiser
Seydlitz into an aircraft carrier.
German Warships, 1815-1945: Major Surface Vessels.
German Warships, 1815-1945: U-boats and Mine Warfare Vessels.
German warships of the Second World War.
For a complete list of sources