So many eloquently put posts.....Words simply fail me today.
I do think that, no matter what fellow PPRUNER's views of the USA may be (Winston Smith), they are entirely irrelevant today and in this context always will be. This is beyond doubt a series of tragedies only ever heard of (if then, and certainly not involving large civilian aircraft) in situations of war. Nobody could ever be accused of asking for THIS. I still cannot get my head around any of it.
My thoughts really are with each and every person affected by this utter tragedy.
My deepest sympathies to all concerned.
Clearly the worst day for aviation ever in my humble opinion.
USA airspace now closed until 2359z on September 12th.