Fun fact: when they tell you to turn off all personal electronic devices on a plane during takeoff, it has absolutely nothing to do with interference. Think about it, if you live in a big city, or even in a town with like, more than two people in it, your phone is being exposed to likely thousands if not millions of stray signals every day, and it can block them out just fine, of course multi-million dollar airliners can do the same. If that wasn't the case, planes would drop out of the sky every time they flew over any land that wasn't completely uninhabited. All airports would have to be in the middle of the desert, or in some other remote corner of absolutely nowhere, just to not be death traps for any plane trying to make a landing.
The real reason is just because they want you to pay attention during the safety demonstration.