No, you're still not grasping the difference between those situations. Double-blind trials are required in situations where the results are subtle enough to be colored by personal expectations and biases. Large-scale trials are required when reasonably different conditions (e.g., different human test subjects) could produce radically different results, when it's impossible to tell whether a single test subject is an average or an outlier.

Neither of these conditions apply to the question "Can this airplane fly or not?" There is no subtlety there, no biochemical variations. The plane either flies or it doesn't, and either result is perfectly clear to even the most ignorant layman.

As for peer review, the Wright Brothers had plenty of it: their peers showed up, looked at the plane in flight, and said "Yep, uh-huh, that's flying all right."