[Capt. Tom]

What about the plane piece that was found in the ocean, and confirmed to be from this plane.

I was wondering about that also.
The site they are searching is well inland and unlikely to have plane parts reach the ocean. - Tom

[Zhang Fei]

https://www.cnn.com/2017/03/08/asia/mh370-debris-found/index.html

[BradyLS]

...unless an interceptor hit it the passenger jet over water (or the coast) with a missile and the decompression blew out debris from the craft that drifted on the wind out to sea while the plane descended to crash further inland...?