EU Climate Commissioner Connie Hedegaard is an idiot. Does she not see the what will happen?
i.e. EU pressures one member state (probably Denmark, nice but naive) to impound a Chinese aircraft.
Then;
Chinese airlines stop all flights to the EU, to not risk having their aircraft impounded. Indian airlines do the same.
EU airlines stop all flights to China and India - they don't want their aircraft seized there.
China and India ban overflights by EU airlines, causing delays, diversions and cancellations. EU countries retaliate and remove 1st freedom rights for Chinese and Indian airlines.
US, Canada, Russia decide to support their Chinese and Indian friends and ban overflights by EU carriers. 3rd/4th perhaps can continue but 1st rights are removed.
i.e. BA can still fly to the US, but not over Canada. AF can still fly to Mexico, but not over the US. Both can still fly to Singapore, but not over India, China or Russia.
Is it worth it? Well Connie hates aviation (although she always flies First Class) so she won't care.