alt Hacker Newssafer to hedge ones bets. The absence of evidence is not the evidence of absence. We could dig up a dinosaur equivalent of a 747 tomorrow.
also, recorded history pulls double duty here limiting the record to earth. You never know what those shady schmucks in the delta quadrant are up to...
> The absence of evidence is not the evidence of absence
We have plenty of evidence to suggest that no other known thing that we have ever encountered on Earth either living or as fossils would have been capable of building an airplane
You're right that we have no direct evidence that there never were airplanes before humans existed, but with the evidence we do have it would be downright absurd to suggest we can't make a statement about that with some authority