Vladivostok offered a comparatively straightforward landing place for the bombers, but Soviet neutrality toward Japan ruled it out of the plan. The crews therefore had to continue to China. Soviet forces concentrated against Japan operated at the distant end of their supply network and could not simultaneously cover the German border. The recovery route depended on the Soviet Union's wider security and logistical position as well as on aircraft range.
Notable Point · 1:53:00-1:54:11
Soviet neutrality and the Doolittle bombers' recovery route
Soviet neutrality ruled out the intended Vladivostok landing, while the difficulty of concentrating forces against Japan and Germany explains the wider strategic constraint.