Unfortunately none of Whitehead's work can be seen to have demonstrated any input whatsoever toward the development of a practicable aeroplane.
That is, I think, at the root of it.
If somebody's achievements are to count, then they need to have done what they did in a manner which allows other people to build upon it.
Even the Wrights with their obsessive attempts to protect their intellectual property did publish what they'd done and do things in a way that allowed other people to build upon their efforts - and as such deserve a lot of credit for that.
Incidentally, noting the RAeS disclaimer - the society is generally pretty rigorous about such things. I've published two papers in their
Journal of Aeronautical History and the refereeing was rigorous and thorough; technical papers I've published in
Aeronautical Journal equally so.
G