I have to give kudos to Airbus for having the guts to do this using five test A350-900 XWB aeroplanes, its newest wide-body airliner. I know the stunt was well calculated and the pilots — all of them ex-military aviators — knew exactly what they were doing, but the entire thing still looks insane.
Especially when one of the planes is the one they have just delivered to Qatar Airlines — this was filmed in September, to celebrate their certification by the European Aviation Safety Agency. It's one thing to do this with jet fighters, but these are 213-foot (64.8-meter) wingspan flying beasts.
The action starts at 3:35 into the video. [Thanks Andrew Gorenstein!]