It seems from this thread that the criteria have now been "stretched" so that only those with a scientific background qualify as important pioneers.
So for those who want "Aviation Science" to be a criterion for determining pioneering achievements, learn about Cayley here:
https://en.wikipedia.org/?title=George_Cayley
He set down the scientific principles for flight in 1799, quite a long time before Wright, Whitehead, Ader and others.
Look too at the Royal Aeronautical Society, founded in 1866:
https://en.wikipedia.org/wiki/Royal_...utical_Society
Look too at Stringfellow:
https://en.wikipedia.org/wiki/John_Stringfellow
If these are not American enough to be considered as significant to Flight, consider that Chanute and the Wright Brothers, and many other pioneers were avid readers of every paper published by RAeS.
(These links happen to concern British aviation, but I do not ignore or dismiss the contributions and achievements of many others around the world!)