Most of those entities are empty shell companies to hide paper trails. WSJ report via dailykos to avoid paywall: https://m.dailykos.com/stories/2016/12/8/1608674/-Donald-Tru...

“President-elect Donald Trump owns a helicopter in Scotland.

To be more precise, he has a revocable trust that owns 99% of a Delaware limited liability company that owns 99% of another Delaware LLC that owns a Scottish limited company that owns another Scottish company that owns the 26-year-old Sikorsky S-76B...”