I have to give kudos to Airbus for having the guts to do this using five test A350-900 XWB airplanes, 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 are delivering today to Qatar Airlines (this was filmed in September to celebrate their certification by the European Aviation Safety Agency.) One thing is to do this with jet fighters, but these are 213-foot (64.8-meter) wingspan flying beasts.
The action starts at 3:35. [Thanks Andrew Gorenstein!]