First Flight criteria
Shouldn't the airplane being considered for first flight also be aerodynamically capable of first flight?
In the Ader example I would interpret the "gust of wind" to be strong enough to physically move the weight of the apparatus but if the airplane was not designed such to be "airworthy" then it could never be considered as first.
Regardless of how it gets into the air, the first flight airplane must be capable of sustaining itself in the air once it was there.