How is it that they can track a missing iphone but not a missing airplane from egypt?

How is it that they can track a missing iphone but not a missing airplane from egypt? - 1

IPhones don't go missing at 35k feet over a large body of water.

For one, cell phones are tracked by cell phone towers and I honestly doubt that Sprint and AT&T are building cell phone towers in the oceans when they're busy cutting back data allowances and jacking up prices.

You are not taking into account the fact that
if there's no trackable signal being transmitted from the lost object,
there's no way to find it without physically looking for it.