I am a bit boring, but I carry a compass. Coming back from AUH today it was showing us flying in a south easterly direction when we should have been going north west. I naturally assumed we had been hijacked but spotted the Greek island of Santorini (it has a very characteristic shape) drifting past in the correct direction so all seemed well. Later, over Belgium, it had us flying north east rather than north west but by that time I was too drunk to care.

Do compasses behave differently at 36,000 feet?