Mystery missle launch in California?

Ok, the title of this thread might make you think this is a military issue, which doesnt belong in the Commerical Aviation section of this forum, however, in the article below it says that there was a mystery missle launch in the Pacific Ocean (approx 35miles off coast of California), and so far there has been no rational explanation for it, not even from the military!

The article does mention though that “physicists said the trail was left by an aeroplane, and that on a clear day the vapour created an illusion making it appear to rise vertically”…could this be true/possible, or do I detect the smell of a possible cover-up?

http://www.bbc.co.uk/news/world-us-canada-11721981