Burial
DS
Mythbusters were using bullets. In the a/c situation the preceeding pieces make a swathe for the following bits and it is nor comparable. I reiterate that I've seen real a/c buried and there are the instances of Sil Air and others. I'm not implying no possible wreckage, but perhaps sufficiently little to be noticed. Some may drift to the surface later if the mud is fluid enough.
I'm not an absolutist like so many here addicted to closure. I'm happy to keep juggled balls in the air. I consider the buried a/c scenario my lowest priority, but I can't rule it out.