It's one of two things: He's nuts, or he is using his background in MI two screw with a segment of the population, and their elected leaders for personal gain.
In my experience around people who work in intelligence, someone who hints at some fantastic event, but then refuses to provide details, and or evidence because "it's classified" is full of crap. Legit whistle-blowers always have documents, photos, and or video when they go public.
Let's say the US Government does have recovered alien craft under s secret project that dates back to 1947. There have to be millions of pages of reports. There have to be miles of 16mm, and 35mm film stored in film cans stacked on shelves in temperature-controlled warehouses. And there has to be an equal amount of video tapes, and now digital media. So where is it? Those of you who work in or with the government know how much paper is generated each month. Even if these files are on microfilm there still has to be a monstrous amount of storage. And if such a project exists all of that material would be housed in a central location under tight security, at a location fairly close to where back-engineering is conducted.
Nothing has ever leaked. Nobody has ever talked. SOMEBODY ALWAYS TALKS.
We know about the F-117 program in some detail even though they operated in the black for several years. A large-scale attack aircraft squadron with mechanics, and dedicated KC-135 crews did their thing in secret out of Tonopah, NV. But the locals knew something was up. US Army anti-aircraft crews told stories about a plane they couldn't track, but heard fly over in the desert. By 1985 I'd heard about something flying at night out of Nevada, and I just worked in a hobby shop.
Somebody always talks. Yet no one in almost 80 years has ever come forward with details, or pictures, or documents. In the USA, this is impossible.
Elizondo is playing people for suckers.