a2+b2=c2 - The French air traffic controllers are on strike...
… and thus you have to fly around french airspace when you are going from Amsterdam to Lisbon and back. Takes about an hour and twenty minutes more than the direct route, but creates a somewhat beautiful route display on the in-flight entertainment system:
Also reminds me of a picture i took like three years ago in the train station in Strasbourg. you simply gotta love the french (seriously! for lots of reasons!)