Two classified UFO shapes?

[Sirius]

Such technology would revolutionize aviation; or at least a major segment of that field. Which would have serious economic impact if it became public.

I'm not convinced economics is a big factor.  The economic impact can be controlled, more likely it would just put the elites further ahead. It can be released with limitations and made expensive.

Unless it's really basic martials and methods and that would have to be hidden by diabolical measures. The nature of such constructs would be to come to light.