When I was told the story of the buried aircraft the story tellers didn't know what sort of aircraft they were , just WW2 aircraft , I imagine fighters , I doubt they'd be Mustangs
Under USA Lend Lease the equipment had to be returned (which rarely happened) , purchased by the recipient country (UK purchased a lot of equipment at 10 cents in the dollar) , destroyed or scrapped
Lot's of fighter aircraft pushed off ships off the east coast of Australia.
There's also a lot of stories about trenches being dug and aircraft pushed into them and filled in with dirt.
Like most legends 90% of them are bull , especially 'new aircraft in crates' stories , I personally heard of some 'new tiger moths' in crates near Goolwa South Oz , a few years later I actually found them by coincidence and they were very well worn disassembled tigers sitting in a farm barn , some of the bits were in crates :-)