1869 Scientific American [Major mainstream American science publication]
“When man can make a structure as strong, as rigid, as elastic, as light in proportion to bulk as a goose quill, the problem of flight will be nearly solved.”
https://www.scientificamerican.com/article/is-a-flying-machi...
1888 Joseph Le Conte [Prominent American scientist and UC Berkeley professor]
“A flying-machine… is impossible, in spite of the testimony of the birds.”
https://en.wikisource.org/wiki/Popular_Science_Monthly/Volum...
1902 Lord Kelvin [President of the Royal Society and one of the most prominent physicists of his era]
“No balloon and no aeroplane will ever be practically successful.”
https://zapatopi.net/kelvin/papers/interview_aeronautics_and...
1903 The New York Times [Major mainstream newspaper, 69 days before the Wright brothers’ first powered flight]
“Nature is more successful in applying the law of compensations to the correction of errors of design or development than man has ever been or is ever likely to be.”
https://en.wikisource.org/wiki/The_New_York_Times/1903/10/9/...