In the book Visions of a Flying Machine (about the Wright brothers), the author's answer to this is "definitely." If the Wrights, and Santos-Dumont had failed,

In the book Visions of a Flying Machine (about the Wright brothers), the author's answer to this is "definitely." If the Wrights, and Santos-Dumont had failed, someone else in the world would have come up with a practical airplane within the next year or two. There were certain enabling technologies, like more efficient motors, that made it possible. Understanding of gas dynamics in academia was very high (Ludwig Prandtl was studying supersonic flow in tubes at the time), though fluid mechanics not as much. This is apparent in how rapidly aircraft development proceeded around the world after the Wrights, and how it left the brothers behind despite their patent protection attempts.