“Please turn off all electronic items including mobile phones, laptops and game centers as they may interfere with the aircraft navigation systems”

There have been many studies into all of this nonsense and there is not a shred of evidence to suggest electronic devices interfere in navigational systems or any other system for that matter.  Even if you tell the cabin crew your device has been put in “Airplane mode”, they insist on making you switch it off just to prove they are the boss of you.  The other point that always puzzled is this: When we are in mid air, don’t they use navigation systems? After all, we are allowed to use the very same machines once the aircraft is airborne.