It is perhaps even more startling to recognise that if you set off from Amsterdam going due East, you would end up in Western Australia!
Am I thick, I dont get it. Please explain!!
A totally stable aircraft, ignoring all external influences, will not maintain a heading. Instead it will maintain a Great Circle. That simply means that it will fly a circle around the centre of the Earth.
What that effectively means is that if you set off going due East at 50 degrees North then by the time you get to the opposite side of the globe you will be travelling due East but at 50 degrees South.