I have carried several kilograms of gold through TSA screening checkpoints a half dozen times. I know that GP pre-edit was talking about $50mm but it is practically quite straightforward and entirely legal to fly domestically in the US with $0.5-1mm in gold. The risk of civil asset forfeiture is another matter but in 6-8 times I have never personally felt at risk from such.

>Let us know how you get it through airport security.

How you get it through what now? Private aircraft don't deal with that. GP did specify "billionaire", and at that level at least fractional ownership in private long distance transportation is not a reach either.

The point is that transporting large amounts of money that can be physically confiscated is a problem, even if it somehow fit into a suitcase.

Debating the logistics of potentially being able to evade some of those difficulties by having even larger sums of money (to afford private airliners or private security, even in times of unrest) and accepting larger risks misses the point.