Vuia The sources clearly state that there is no documentary evidence. Even the L'Aerophile article makes this clear. Furthermore the first footnote in the article clearly states that SOME accounts credit this flight, but does not itself credit it. This is not consistent with saying that such a flight definitely happened. Saying later that it definitely happened is contradictory.
 Even if you haven't read the sources that make clear that the claim in question is based on no documentary evidence, that is no excuse for saying it definitely happened in contradiction of a reliable source saying that only some sources make this claim.