Reading this makes me wonder how accurate our historical records are. And then I think of this.

http://pbfcomics.com/209/

I think the huge difference between the Wright brothers and everyone before (and contemporary) to them was that they devoted a non-trivial amount of time to the testing, measurement and understanding of airfoils in their wind tunnel. Before that everyone was guessing. They produced accurate scientific data before deciding how to build their next generation aircraft. Revelations such as wing aspect ratio as a performance factor were crucial. Wing and propeller airfoil selection was also done scientifically.

NASA has a great deal of information about this.

https://www.grc.nasa.gov/WWW/K-12/airplane/wrights/results.h...

Richard Pearce is our contender for first flight - possibly before the Wright brothers. https://en.m.wikipedia.org/wiki/Richard_Pearse

Poor Franz Reichelt, also, sadly...overlooked. But he did make a great movie and left quite an impression. https://en.wikipedia.org/wiki/Franz_Reichelt

And Lawrence Hargrave

https://en.wikipedia.org/wiki/Early_flying_machines#Kites

Not powered, but still a significant pioneer.

That whole WP page gives a good perspective.