There was a hoax alien photo associated with Varginha but I have never read a thorough debunking of the Varginha incident. As far as I know, it's still a mystery.
http://www.usnews.com/news/articles/2012/10/19/ufo-sightings-pose-danger-to-aviation
I just stumbled over this (above). US News And World Report is pretty mainstream. Of course, they throw in some balloons to back away from asserting too much but I understand that some pilots have been terrified by near collisions with UFO's.
While these ET remains may have been hoaxes so far , I remind myself that 'they only have to be right once'!
metatron