>>11986620lb/pb
Not all that far for an aircraft then.
I think most/all crafts people see, are government tech being tested.
This plane for example, was being tested right around the same time as Roswell(only a few months apart from each other).
https://en.wikipedia.org/wiki/Northrop_YB-49
Granted it isn't "saucer" shaped, but it is pretty easy to fuck with people's perception/memory. Very malleable. (comics had been beating the UFO 'saucer-shaped' drum for years already, and expectation can shape perception).