I believe the answer is war. If there is a class of folks outside of "the inventor" that you can risk on an experimental aircraft, it's soldiers. WW1 happened

I believe the answer is war. If there is a class of folks outside of "the inventor" that you can risk on an experimental aircraft, it's soldiers. WW1 happened very quickly after the invention of the plane and there was a huge explosion in quantity and type of airplane in WW1. I'm no historian though, there could be nuances I'm missing.