Maybe you should be thinking about the specific disruptions that will result from a black swan event and then plan accordingly. Not all may happen at the same time.
1. border (movement) controls, forced military conscription

relocation plans
2. capital controls, asset seizure

offshore liquidity
3. electronics disruption

non-electronic assets: cash & coins, physical gold, real estate titles, physical share certs
4. national currency collapse

foreign currencies including gold
5. food & water rationing

emergency supplies, relocation plans
As to the details, is up to the person to plan depending on wealth abilities (net worth). But relocation plans is always popping up in many scenarios. I would prioritise it as 2nd after gold.
Air traffic can be closed, but land & sea crossings may still be open. US stopped passenger air travel in Sept 2001 but did not close the land borders of Canada and Mexico for crossing because commercial trade still need to pass through.
https://www.cbc.ca/news/world/coronavirus-covid-19-border-canada-united-states-trade-1.5503192"
Operating on a case-by-case basis, U.S. border agents began waving through the cargo and travellers they deemed low-risk."