Zeppelin Flight. 1936 (April 10), cover franked by complete air post set of five values, tied Copenhagen ''7.4.36'' ds, prepared to be delivered by Airship Hindenburg on 1st North America Flight (May 6-14), bearing Friedrichshafen ''10.4.36'' connection and red oval confirmation marking, however was not posted on the flight and delivered to Fredericia on May 6, minor reversal soiling at corners, still F/VF and scarce, Est.,. $150-$200 (Image)