Yesterday I made a new flight using the flight planner from EKCH to KJFK, Kastrup in Denmark to New York. Now the flight planner decided I need to take a route to first UK and then up over Greenland, this I can understand. But then the rest of the route was from greenland and over to the alaskan border, make a left turn heading down to New York...this doesn't make sense, or does it?

No, it doesn't make sense but maybe you should invest in a proper flight planner like FSBuild 2 or even the freeware FS Build 1.40 version.http://www.fsbuild.com/This works for me everytime. :-)

Sounds like the FS2002 planner. My flights from Boston to London went via Africa.