Since we've detoured from buried jeeps, to buried planes. There are rumours of underground storage hangers with a variety of intact planes, under old German airfields.
Confirmed burials of WW2 planes are from the Phillippines, where hundreds of planes were bulldozed into holes & buried.
Underwater dumps of vehicles are fairly common in the Pacific theatre too, tales of equipment being offered for sale to the locals; who thinking that it'll be left behind anyway, so why buy when they'll be able to just acquire it when it's been abandonned?; the vacating Allies just drive anything into the sea, preferably off a jetty or a cliff.