FOIA websites on various government sites. However, they are indexed horrendously, and with no rhyme or reason really... Of course, that's probably on purpose, hehe.... Thing is, they are only there as the result of a request, and you have to be pretty specific with the request, so it's still slim pickings... Still, some amazing stuff there, showing you just how seriously this matter (UFOs) was taken back then.

majesticdocuments.com is another great source, but know that some documents aren't rated as high as others confidence-wise. These guys subject the docs to a battery of tests to try and authenticate them, so pay attention to the indicators of this, as some frauds are likely there.

Older folks in this board know what our fathers went thru during the WW2.
My Dad set-up AA in North Africa to help the English, in a valley, so close he could see the Jap faces going by in the plane...and good bye.
Went to England, showed the young guys to shoot the 50 cals out of the B-17's in the runs over Germany. 10 missions over Germany in the tail on a B-17. So shot up coming over the English Channel, pilot asked if they wanted to bail...made it by feet.
Didn't tell me this till my early 30's, The horror of war. UFO's were no bid deal to these guys.
Dad had many footlockers I went thru, remember the "top-secert" files he had. Had the weird foo-fighters, even at a young age, though it was strange.
Born in Newfoundland, grew up in California and upstate NY, Dad sent up a Huge Radar Base in Greenland after the war.
Finally told me of a massive solid object reading, and sent up the multiple jets to the bogys. A big deal. The jets hit the mark, and nothing seen.

Very unlikely a rocket hit an ETV.
But I read high powered radar and other high powered particle beam would hit them. In the case of roswell, I would think High powered Radar.