Aircode is a fairly new style of playing didgeridoo, largely pioneered by Dubravko Lapaine. Its not dissimilar to beatboxing but you are limited and exclamated to the innate frequencies of the tube. Long, cylindrical, and tightly-toleranced didges are the tools of the expression, which I've been making for some years now.
These two : "Ikigai" a 432 F# with C# aircode at 8.5ft long, and "Eye of Jupiter" a 432 A with E aircode at 7ft long.