TR-3a Black Manta or Aurora ... definitely an experimental aircraft from some black project. Probably the main reason why area 51 and Groom Lake are still shrouded in so much secrecy and being kept from public scrutiny with air tight security.

People must have spotted these things many times, but lacked the proper photographic equipment to document it. Up until know it was just hearsay and speculation.

It's basically a high tech toy for and by grown-up children with way too much dodgy funding at their disposal. Just imagine how many hundreds of billions must have gone into the development of just 1 prototype ...
Still wondering why there's so much misery in this world?