One should like to think that something like this was about economies of scale, boosting productivity, expanding new markets and the like but, regrettably, I believe it is quite possibly driven by European and global politics more than by sound fiscal rationales.
The entire merger with EADS, from what I read, seems to lack any effective impetus from our side to preserve let alone protect British interests.
It seems to me as though Britain's aviation industry (in the proper sense of the word) was an idiosyncracy of the first half of the 20th century and which isolation from our modern world I find very sad.