Needle in a haystack
Low density ceramic that was crumbled at 35,000' plus over the ocean and spread by wind and waves could fetch up anywhere from Lagos to Iceland.
Weather tracking would help narrow the search, but it would be difficult.
In any case, I bet a few shards of tile crumble on every mission. Hard to tell the difference?
Good lateral thought, though, that the tiles had "sprung" on ascent