That will surely make waves across Europe: Airbus is thinking about outsourcing one of the A330 assembly lines in China.

Airbus has a history of complex deals to satisfy all the national stakeholders—mainly France and Germany, but also Spain and the UK, providers notwithstanding (just look at how they organized the various offices and HQs, just to make everyone happy).

Although it's not the first time this would be the case (the A320 has a dedicated assembly plant in Tianjin since 2009, a joint venture held by Chinese partners in majority), it's undeniable that discontent shall rise again, especially amongst French unions and politicians. 

As the linked article notes, the US has seen a spectacular change in its production costs that makes it very competitive compared to China.

This is mostly thanks to lower energy prices due to fracking but also to labor flexibility.

Europe is thus more expensive overall. In other terms, Airbus is at a relative disadvantage to Boeing.

Airbus CEO has been hinting at expanding final assembly in low-cost markets for while now.