Contract signed 1948-11-23 by Smithsonian and Wright heirs
The contract shown in its entirity at the bottom of this page contains an unusual clause (also shown in red, immediately below). In it, the Smithsonian Museum cedes its right/duty to objectively investigate and represent aviation's origins. Instead, it contractually commits itself to always state the Wright Aeroplane flew first.
Besides the obvious surrender of a museum's core function, the contract's bloated legalese is "semantically challenged". It refers to "aircraft" (a word encompassing balloons and airships, many of which were motorized and flew before December 1903):
"d) Neither the Smithsonian Institution or its successors nor any museum or other agency, bureau or facilities administered for the United States of America by the Smithsonian Institution or its successors, shall publish or permit to be displayed a statement or label in connection with or in respect of any aircraft model or design of earlier date than the Wright Aeroplane of 1903, claiming in effect that such aircraft was capable of carrying a man under its own power in controlled flight.”