Yea I believe that the whole logo reads W.DONOVAN D CORPORATION, i tried finding behind the scene photos of the plane and i've discovered the plane model was Douglas C-47B-35-DK Dakota IV Registration N170GP, c/n 16688. Carried military serial 44-77104 and that the scene with it was filmed at North Weald Airfield I found a photo of the plane with the logo at a flat angle but can't find it in high enough resoltion. hopefully this infomation can lead to a decent readable photo of the logo.
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