From 7th Feb Flightglobal:
I wonder if the pointless scrabble to get deliveries into the last month of the year rather than the first month of the next year is very disruptive to production. I find this a pretty dumb way of doing things since you're robbing 2017 Peter to pay 2016 Paul, so compromising 2017 figures. Of course if you repeat the stupidity in Dec 2017 you can recover that loss but what useful result is produced by making your operation more expensive in this manner?
It also depend on where in the production chain you look at, adjusted for the 1-2 holiday, the flow through the FAL is stable and does not follow the rush and droughts as we see in the deliveries.
It is important to Airbus because their reporting and financial year ends in December - so it affects the whole company and its share price. But I agree, they must try to work harder all year round so that there is less of a mad rush in December.
Equally or more important for airlines as the asset can be depreciated in the books if delivered before end of the year.