The unit suffered from the poor serviceability and low production rates of the Fw 200 bombers, and from repeated diversion of its long-haul capability aircraft to undertake transport duties in various theatres, especially for the airlift operations to supply encircled forces in the Battle of Stalingrad.[1] Later in the war, KG 40 became one of several Luftwaffe bomber wings to use the Heinkel He 177A heavy bomber.