Hey I'm not the scientist, you can easily do your own research on how volcano ash spreads, dissipates in the upper atmosphere, etc etc etc. So Google it. I have less time than I did over the weekend to research and post this stuff now that my kids aren't sick.

Btw, this link that I added in the updated section earlier has real-time air traffic plus the ash cloud.
[link to www.radarvirtuel.com]

I can tell you that I read that some of these models of the ash cloud were/are incorrect. Not surprising really. Humans are not infallible.
Do I think they over reacted? Yah, probably. But, better to be safe than sorry, yes? I would imagine the next time something like this arises the reaction may be a little different.