Tracking, or finding an aircraft over a large ocean area is still not possible. As this article says[1], "About 85,000 square kilometres of the 120,000 square kilometre search zone has been covered so far." But if you match that against the map of the search area, you will see that even that huge search area covers only a narrow strip of ocean.

The plane may be huge, but compared to the earth, it is very, very small.

[1] https://theconversation.com/two-years-on-since-flight-mh370-...