Setanta is right on the money. The Roswell UFO crash -- and we have to label it a UFO as, at the time, it was an Unidentified Flying Object -- was. quite obviously, a US gummint project which went astray and came down where it wasn't supposed to. Several things need to be noted here by anyone who wonders why an innocent accident like that should be classified. For one thing, this was 1947, just two years since we had unleashed some nuclear weapons on Hiroshima and Nagasaki. We were still the only country in the world to have a nuclear capability and wanted to keep amything connected with nukes out of public view. A little known fact is that at the time Roswell airport (today part of the campus of Eastern New Mexico University-Roswell) was one of only two places that had the capability of sending nuclear-armed aircraft aloft. The other was the Almagordo base at White Sands. Between these two bases, I'm sure, some very hush-hush experiments were going on.
I've heard a theory while visiting Roswell that really appeals to me. There are people who believe that the Federal government actually encouraged the 'flying saucer' theory when some sceptics didn't want to buy the 'weather balloon' yarn. They pretended to pooh-pooh it in such a way that most people would conclude right away that the denial was disingenuous. The Army thought it was great that people believed there had been a cover-up of an alien landing rather than a cover-up of a secret Army project. That makes perfect sense to me.
BTW, the whole story has been a bonanza for the residents of Roswell. It's the only reason the burg has become a tourist destination, with busloads visiting the UFO Museum on Main Street and gawking at anything that has even the most remote connection with the 1947 event. There ain't much else in the town to attract anyone. Oh. I almost forgot. There is one other thing. Roswell claims it has the largest mozzarella cheese processing plant in the world. But I doubt that anyone comes to town to get a tour of the cheese-works.
