I've heard from others who are researching the issue that there was no NOTAM. Also, people in the amateur rocketry community are being asked if this was one of theirs.

My guess: contrail + some people in the gov't bought the missile angle, but there was no missile. So now some officials are worried that someone launched a missile that they don't know about.

Agreed. There's a picture here of a similar-looking jet contrail: http://lewis.armscontrolwonk.com/archive/3136/it-aint-no-thi...