It's seems a Durian Tree.
I believe these trees develop better if grafted to a different rootstock, so there is no point in doing an air-layer so the tree can produce their own roots (these also seem difficult to air-layer successfully).
By grafting the rootstock roots and doing an air-layer, at the same time, you allow the graft to heal while using most of the energy produced from the leaves of the grafted branch and at the same time that energy is used to produce roots.
I believe that most of the roots that develop in the air layer are from the rootstock that was grafted. Those that, eventually, develop, at the girdle point, are probably discarded when the air layer is removed.
The method used seems to be a modification of Inarching combined with an air-layer.
The reason for that seems to be that Durian is difficult to propagate from other methods:
"Propagation
Durian seeds lose viability quickly, especially if exposed even briefly to sunlight. Even in cool storage they can be kept only 7 days. Viability can be maintained for as long as 32 days if the seeds are surface-sterilized and placed in air-tight containers and held at 68º F (20º C).
They have been successfully shipped to tropical America packed in a barely moist mixture of coconut husk fiber and charcoal. Ideally, they should be planted fresh, flat-side down, and they will then germinate in 3 to 8 days. Seeds washed, dried for 1 or 2 days and planted have shown 77-80% germination. It is reported that, in some countries, seedling durian trees have borne fruit at 5 years of age. In India, generally, they come into bearing 9 to 12 years after planting, but in South India they will not produce fruit until they are 13 to 21 years old. In Malaya, seedlings will bloom in 7 years; grafted trees in 4 years or earlier.
Neither air-layers nor cuttings will root satisfactorily. Inarching can be accomplished with 50% success but is not a popular method because the grafts must be left on the trees for many months. Selected cultivars are propagated by patch-budding (a modified Forkert method) onto rootstocks 2 months old and pencil-thick, and the union should be permanent within 25 to 30 days. The plants can be set out in the field within 14 to 16 months. Grafted trees never grow as tall as seedlings; they are usually between 26 to 32 ft (8-10 m) tall; rarely 40 ft (12 m)."
It seems patch-budding would be a better option but this method will probably produce a bigger tree quicker.
Thanks for the link to the video. Very interesting method that allows the use of a large scion branch and doesn't need a larger diameter rootstock, only some of it's roots.