I think part of it is that the flight staff want you to pay attention during takeoff and landing. Having your headphones on/in means you're not listening to the

I think part of it is that the flight staff want you to pay attention during takeoff and landing. Having your headphones on/in means you're not listening to them. Another part is that the flight staff wants fewer things potentially flying around the cabin if there's trouble. of course, they don't usually ask you to put away books... Cell phone companies want you to turn off your phones because they mess with the ground towers. Flying past towers rapidly puts load on the cell network to transfer your phone's connection between towers rapidly. Your phone can also see more towers than usual, causing it to possibly flap between them in unexpected ways. The bit about it being unsafe due to messing with the plane's avionics is total bunk, though. I never turn off electronics on flights, except to save battery.