Show us a piece of what these so called “spacecraft” are made of. Just one piece.
He can’t. No one can. Because there have never been any such vehicles or beings here.
Go to
Linda Moulton Howe has pics of a bit of a UFO that documents the often found multilayered composite--bismuth, magnesium and I forget the 3rd substance. IIRC, the layers are only a few atoms thick.
There is even an organization that has been dedicated for 15-20 years or so to investigating UFO sites for tangible trace evidence (including soil indentations, scrunched limbs etc). The group is composed of scientists who have taken their tasks quite seriously and have a surprising amount to show for it.
BTW, that sentence is simply wholesale false.