Blanche writes:

Roy Smith wrote:

Along those lines, I think the most important thing to take on any trip
in a small plane is a fully-charged credit card. It can buy you fuel,
emergency repairs, dinner (or a hotel room) while you wait out weather,
a rental car, or an airline ticket.

Cash. Always accepted. Never refused.

Cash won't work at automated airport fueling stations without an
attendant (e.g. after-hours) in the US.