Looks like it is done with adhesive vinyls then. Basic all-over single paint coat as standard (usually white, of course, but black here), and then all the white detail and pattern applied by preprepared decals. The production and application of these is the only extra cost and time.
The clever bit is unfortunately not shown in the clip, it's the computer-controlled large printer that does the adhesive material and cuts it to size.
I believe the BA "World Tails" from some years ago used this technology to best effect.
I agree with the comments about black being known as a poor colour for the upper parts of an airframe (which is precisely why the majority use white, including all the rest of the Air New Zealand fleet), the lack of reflection of solar energy causes a significant increase in temperature on the upper skin and inside. Bear in mind jet aircraft are meant to spend most of their time above the clouds. If nothing else, it causes a measureable increase in fuel consumption because of the increased cabin air conditioning requirement to maintain the standard desired temperature. Now I know Air New Zealand can't help what colour is associated with their national team, but it will show up in the operating costs.