Well, it could be a a US Black Project, but it just doesn't make sense to be one. Why go through all the secrecy of developing such a Black Project aircraft to then make it so widely exposed? I guess it could be for "softening" up the general public for an eventual disclosure. But...this doesn't explain why this is happening in other countries as well, particularly in the UK. If they are human craft, it is till hard to get past the reports that they can submerge into the ocean then fly out of the water at high speed. Of course these reports could be inaccurate.
Here is an excellent video on all possibilities, plus a most recent photo of one of the craft that is sure to raise eyebrows and concerns that it still might be of off world origin. This story has such an underlying creepiness to it.
Here is an excellent video on all possibilities, plus a most recent photo of one of the craft that is sure to raise eyebrows and concerns that it still might be of off world origin. This story has such an underlying creepiness to it.