The initial aerial search efforts by sizeable numbers of multiple engine aircraft, with multiple searchers aboard - that produced precisely nothing - is what remains the most disconcerting feature of the whole MH370 search performance.
I disagree. Aircraft did sight wreckage, but much of it was never investigated due to the remote area it was found. It is hard to determine what it is from the air, and I've done a lot of looking at the ocean from a P-3 Orion, one of the aircraft in the search.