Edit: I am utterly wrong about my first point, the export controls don&#x27;t kick in til 1,200mph or 59,000 feet; Both much faster and higher than standard commercial jetliners. [1]<p>GPS on your phone can&#x27;t, by US law, work when you&#x27;re in a plane. It is required that consumer GPS devices stop sending data when it is traveling over a certain speed, to prevent them from being repurposed as guidance systems for cruise missiles. Seriously.<p>You don&#x27;t really need it, though. If you&#x27;ve got two or three people on the plane, the signal from when they all turn off airplane mode is a fairly good landing indicator. Takeoff is less steady; You&#x27;re theoretically supposed to turn off your phone when they close the cabin door, but most people I know don&#x27;t until they are actually taxiing down the jetway.<p>[1]<a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;CoCom#Legacy" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;CoCom#Legacy</a>