Just wondering if this isn't a simple case of air piracy.
We know that supertankers carrying crude oil are regularly taken by pirates off Somalia and also incidentally in the Straits of Malacca.
A super tanker carrying 2 million barrels of crude oil is worth about $220 million plus the value of the ship is worth say $50 million for a fairly new ship.
The typical outcome of a hijack of a supertanker is a secret negotiation and the insurer pays out a ransom and the crew and ship are released unharmed.
If this plane was carrying gold the value involved would be twice as high and also many more higher value passengers involved
Give the holding back of certain information, it is not impossible a similar negotiation could be going on.
To be honest if you just wanted to get your hands on a large plane you could charter one - no need to steal one.