Today in History - Nine years ago

1. Airplane stolen, to be used as a WTC like attack
(unlikely due to difficulty of hiding a 777 from satellite recon)

2. Aliens
(because you think like a 10 year old)

3. Angry pilot guy kills other pilot, depressurizes plane and crashes because F you and F society.
Scenarios found on his computer
Acronymed Associations probably know location but disseminating it would reveal capabilities and techniques.

Can we let this die now?
Not until the wreckage is found. It's all speculation and theories until we have evidence. Anyone who claims they know with absolute certainty what happened on that flight is either lying or delusional. Imagine if some weird never before conceived issue suddenly reared its ugly head on a flight and you were the captain and you died along with everyone else aboard, and suddenly people might start to look at and blame you. How would that affect your family? We don't know what we don't know, there's an old saying about assumption that I won't repeat. I'm not saying that pilot wasn't the reason why that airplane crashed, I'm just saying you don't actually know that to be true.