it could potentially get very serious.
The US government have passed legislation that makes it illegal for any US carrier to pay this tax. The EU govenment claim (wrongly) that it will be illegal for them to not pay the tax.
Hillary Clinton has promised "retalliation" if this goes ahead. US airspace closed to EU carriers? US airspace charges to EU carriers? Who knows. But if the US and EU bang heads theres only going to be one winner.
The chinese and russians and indians have also threatened retalliation. - anyone fancy flying east without going through Chinese, russian or indian airspace?
Clearly the EU have not thought this through and are so arrogant that they think their little unelected dictatorship over europe has global powers.
The EU's legal claim is that the EU never signed the chicago convention. All the member countries did but the EU as an organisation didn't. This perverse logic can be applied to pretty much every treaty going - so I'd reakon on some pretty heavy threats from the rest of the world about this fairly soon. God knows why we are still members of this moronic club!