He did at one time however refer to this very subject about the Roswell incident. He mentioned that in the mid to late 40's there was some experimentation with small sized delta winged aircraft that were very fast for the time, I believe they were using some kind of jet propulsion system which was quite ground breaking for that time. These craft were very high in mobility but had one drawback... The controls for the time were quite complicated and needed more than one person to operate the craft unfortunately the passenger capacity was a grand total of one human test pilot.
Because the craft was too complicated to handle for one occupant apparently the item was redesigned for more that one occupant but the weight capacity was to remain the same . He didn't say how many it was redesigned for but that would mean at least two occupants of small or very small stature would be present to operate the craft. Also because of the complexity of the controls it would need to be operated by human pilots rather that with experimentally trained animals. He said that the rest of what he heard that happened that was the main cause of the government cover up had to do with the age of the occupants. Apparently at least one of the pilots was a very small statured adult person and that there was a rumor that at least one pilot was an exceptionally dextarious young male. I think he was meaning that it was a child.
In other words apparently it was one (possibly two) of our experimental craft that went down in the NM dessert.
There are too many death bed reports related to the ET bodies for me to accept that explanation.
Certainly, time will tell at some point.
After WW2, we took plans from the Germans to make aircraft. Many of these became experiments that were tested away from prying eyes. There were a lot of experiments with radar-avoiding craft and supersonic designs.
All crashes were heavily guarded and kept secret. Who knows why they are still secret today.