United States 1933 Graf Zeppelin Century of Progress Flight Germany to Chicago Cover

Cover franked with three 50c Century of Progress (C18), tied by New York machine cancel (Oct 4), with dual GRAF ZEPPELIN FLIGHT / DISPATCHED FROM FRIEDRICHSHAFEN and LUFTSCHIFF GRAF ZEPPELIN triangular flight cachets, endorsed "From Friedrichshafen to Chicago, Illinois", with exposition arrival backstamp (Oct 26), top two stamps affixed slightly over top edge of cover, a desirable flight and attractive franking.