The least-cost conspiracy theory here, is that 'project aurora' type developments sometimes lead to aircraft with unexpected flight patterns and low radar visibility, so the Navy is basically saying 'we don't want to reveal we couldn't detect this, and it was inside a risk window for our defence ring' along with 'this tech exists, but we don't want to say so or confirm'<p>The second least-cost conspiracy is that like 'Corona' with the NSA and donation to NASA, revealing original quality material informs hostile entities of the resolution of current detection and recording devices in ways the Navy do not wish to reveal, since it will alter the advantage in imaging and detection. This is almost the inverse of above: they did detect it, thats revealing in ways they don't want people to know.<p>The most expensive-cost conspiracy (i.e. what i feel is the least likely to survive occam's razor) is "Aliens"
The last big wow moment in defence tech was stealth and the first US stealth plane flew in 1977. The next country to develop stealth was the Russians in 2010!<p>Now consider its 43 years later with computing technology power that was beyond the dreams of the engineers working on stealth in 1975-1977 and with US military budgets that have been at times larger than the rest of the world's spending put together.<p>I'd expect that the current state of the art experimental US military tech would be considered by many to be "out of this world".
if there's aliens out there actually, it is critical to do not let that knowledge be confirmed in any way. Global societies at large are poorly prepared to manage the cultural and practical impact of a confirmed first contact.<p>Not to mention if these guys are bad, it's for our collective advantage to keep the knowledge restricted to the absolutelly minimal necessary people to manage and prepare the rest for the really bad news.