I'm not sure you can always tell from 'body lanaguage', but while I might believe that Fravor and his copilot saw something odd , I would not trust Mellon or Elizondo at face value. Ex intel people always have an agenda. To believe that they suddenly are concerned about disclosure for the public is a bit hard to swallow.
I know one sure thing that Nasa guy who was talking about the Pentagon UFO/ UAP reveal on the 25th June was steepling with his hands all the way thru the interview. Showing his superiority no doubt .