Given his background, its really hard to dismiss this guy as a kook. He could be partially senile—I’d have to listen to him to make up my mind on that score. Conspiracies do exist and secrets can be kept, as long as they are shared by very trustworthy people who are scared of the consequences of speaking out (e.g., losing their pensions and being prosecuted). If this were not true, security clearances would be useless. Dr. Mitchell may be too old to care anymore.
I have a pilot friend who said he’s seen some strange stuff, but wasn’t willing to elaborate. Truth is often stranger than fiction.
Roswell certainly wasn’t no weather balloon.