Onetrack yes I think you are missing a lot,
Look at these numbers, the you may start to understand the difficulties in finding something in an ocean;
RMS Titanic 880+ft long, 90 ft wide and with a mass of 3341000000 lbs , mainly iron was found after 73 years of searching, interrupted admittedly by 2 world wars.
Earharts L10E was 38 long, 55 ft wide, mass 10000lbs, mainly aluminium with some wood and fabric,which doesn't react too well to salt water. Various theories put its likely depth at anything between 600ft (the current TIGHAR claim) and 18000ft, (National Air and Space Museum curator). 10 expeditions in search of it were/are all looking for a needle in a giant haystack. No surprise it is still missing after 76 years