In early December, Donald Trump put on a tuxedo and boarded the private jet of a scrap metal magnate and crypto miner for a short flight across Florida, touching down at an airport in Naples.

There, a long red carpet marked the pathway into a Christmas-decorated hangar filled with supporters of Trump who had paid $US10,000 ($14,000) to $US30,000 for the privilege of attending a party and taking a photo with him.