I've been listening sporadically to Coast to Coast lately, and I agree with the trend in thought that states aliens and some UFOs are more of a quantum phenomenon than, say, a strictly physical space ship.
I think the crashes have got to be mostly, if not all, government or secret ops projects, simply because it makes no sense that an advanced civilization that can travel galaxies in spaceships would then crash upon reaching Earth. The thought that multiple alien ships have crashed here is beyond ludicrous. If they can get here, they're not going to crash.
Depends on what CAUSES the crashes. Sometimes it could be lightening, since with Roswell, it was stormy that time I heard.
Also, who's the say it's accidental....I would not put it past the American government and millitary to purposely take down alien ships. Sorta like in the movie Starman, the aliens get the 'please come to Earth' message, BUT what happens when the alien got here, he/it got shot down and then hunted. I could easily see that happen for real.
Will be interesting when the big day comes....will America announce it...or will it be another country?