I always assumed there's a chosen public facing secret plane with some PR management to represent the secret program in general and there's numerous other behind the scenes secret crafts without the PR.
I also assumed many of the silly rumors of antigravity or whatever planes are intentionally manufactured as part of the PR so if some information of an actual plane leaks it'll be buried with the noise.
This way, the formal channels could say "oh nonsense, that's just silly rumours, The Official Secret Plane is this one over here".
It also puts outsiders at a true zero knowledge position since there's no indication as to what is and is not nonsense.
Then you could have say, a top scientist defecting, taking all the secret plane information with them, write detailed books and lectures exposing all of it and people would just be like "oh, look at that silly conspiracy kook over there! how goofy"
Pretend it's already happened and there's scientifically sound diagrams, correct math, etc... Nobody would be able to find it among the garbage.
At least that's how I'd structure it.
I also assumed many of the silly rumors of antigravity or whatever planes are intentionally manufactured as part of the PR so if some information of an actual plane leaks it'll be buried with the noise.
This way, the formal channels could say "oh nonsense, that's just silly rumours, The Official Secret Plane is this one over here".
It also puts outsiders at a true zero knowledge position since there's no indication as to what is and is not nonsense.
Then you could have say, a top scientist defecting, taking all the secret plane information with them, write detailed books and lectures exposing all of it and people would just be like "oh, look at that silly conspiracy kook over there! how goofy"
Pretend it's already happened and there's scientifically sound diagrams, correct math, etc... Nobody would be able to find it among the garbage.
At least that's how I'd structure it.