Here's what we know:
The plane did not crash. At least, not violently. Had the aircraft crashed violently/uncontrollably then everything inside would have been decimated. Family members of those on board have managed to get through to passengers cell phones, but have not gotten an answer. Why would they not answer their phones? Only two explanations are plausible;
They are dead,
They are being held at gun point/bound and unable to answer their phones.
It is unlikely that cellphones survived, yet the passengers didn't. This strongly reminds me of the Greek "ghost flight", an aircraft which was bound for Greece but never made it. The cabin was not being filled with oxygen, due to a maintenance crew member not returning the system back to automatic. The oxygen masks on commercial planes only give approximately 12 minutes of oxygen. Everybody died of asphyxiation, and the plane went into an automatic holding pattern above the airport, before running out of fuel and crashing. However, if this were the case with the missing airliner, someone would have spotted it by now. Also, why would people have their cellphones on? You all know how it is when you board an aircraft. You are told to switch all electronics off as they can interfere with the navigation. So why would they have cellphones turned on, but not answer? Maybe a desperate attempt for authorities to track them, without being able to answer the phones?
4 passports had been stolen and the thieves boarded the aircraft. 2 of those were people from Iran seeking asylum in Germany....or so they say. All 4 thieves who stole the passports, originating from 2 different countries, booked seats on the plane at the same time, and the seats were booked consecutively (sitting next to each other).
Another commercial airliner made brief contact with the missing aircraft 12 minutes after it went off radar, and by that time the missing plane was deep into Vietnamese airspace, off course. Many people are talking about the black box and how it can be tracked. All black boxes are designed to only start emitting a signal to be tracked if it comes in contact with water. No such signal has been found yet, despite multi-national search and rescue efforts. Safe to assume the missing aircraft is not buried in the ocean somewhere.
Vietnam is scattered with abandoned WW2 airports, a number of those capable of hosting the large aircraft, as well as hiding it.
So, the plane is most likely intact (cell phones connecting yet no answer), black box is not emitting a signal so it must be on land, suspicious activity with the stolen passports. I for one am leaning towards the fact that the plane is likely sitting in an abandoned Vietnamese airstrip out of view to be used as some kind of weapon or ransom.
