Flying in a giant metal object seems to encourage our deepest paranoias to really come out and air themselves like no other activity.
But if you put your phone in flight mode, you're a bit safer, right?
The radiation from a phone signal cannot interfere with the plane's operating system to the extent that it will cause the whole thing to spontaneously combust.
Even if lots of terrorists kept their phones on and watched data-zapping YouTube videos all at the same time.
But leaving your phone on not in flight mode does mean you could give the pilot a headache.
Here's what happens in about three per cent of cases when phones are left whirring away, according to one pilot on Quora:
You may have heard that unpleasant noise from an audio system, that occasionally happens when a mobile phone is nearby.
I actually hear such noise on the radio while flying. It is not safety critical, but is annoying for sure.
Someone else bothered to describe the noise.
It makes a bzzzt-bzzzt-bzzzt-bzzt-bzzt.
Now imagine that noise in the pilot's headphones, while [he or she] is receiving a critical bit of information from ground control!
So there we have it: no need to be paranoid, but it is definitely a common courtesy to hit that flight mode button.