
MH370 is the 2010s very own version of Amelia Earhart, and we may never definitively know what happened; even if the black box somehow washes up on a Tom-Hanks-and-Wilson island, it’ll be beyond repair given the more than five years of aimless swimming.
Its disappearance has irrevocably changed aviation, though.
The FAA has mandated that by 2020 all commercial aircraft are to be equipped with transponders having ADS-B out capability, meaning the plane’s location can be detected in real time.

The Global Aeronautical Distress and Safety System (GADSS) will from January 2021 ensure that airlines report all of their planes positions every 15 minutes. In addition, the International Civil Aviation Organization (ICAO) mandated that on aircraft built from 2022, those flights in distress will have to report their position to air traffic control every minute, and that all underwater locator beacons last 90 days instead of 30.
A further change initiated by the ICAO is the requirement that planes made from 2021 include 25-hour voice recorders so there will be a record not only of the flight but the cockpit preparations.
What one can’t account for is human error and, though a very infrequent event, the mental instability and criminal intent of the pilots. That’s the elephant on the plane; some folk are just nutters undetected by background and periodic checks (if any). In the wake of the Germanwings Flight 9525 crash in 2015, someone suggested to me there should be a system in place for a team of controllers on the ground to remotely override the pilot’s commands were he to go loco. It’s something to think about, however outlandish.
Further reading:
https://www.independent.co.uk/travel/news-and-advice/mh370-malaysia-airlines-missing-plane-disappearance-investigation-final-report-mystery-unsolved-a8803836.html
https://edition.cnn.com/2019/03/08/us/mh370-fifth-anniversary-malaysia-flight-370-space-based-global-tracking/index.html
https://www.theguardian.com/world/2019/mar/07/mh370-five-years-of-theories-about-one-of-aviations-greatest-mysteries