Having worked in both aerospace (GP's comment) and e-commerce (your comment), I can tell you that these are not the same problem and do not require the same solution.
First week on the job in e-commerce, I educated the junior engineers on the problems that can arise when using floating point math with currencies, then prioritized work to remove any floating point math from the code. That doesn't mean I wouldn't use floating point anywhere else. In aerospace in particular, I've used floating-point without issue, so I don't think you're point about currencies has any relevancy to the GP's comment regarding fuel estimation.
First week on the job in e-commerce, I educated the junior engineers on the problems that can arise when using floating point math with currencies, then prioritized work to remove any floating point math from the code. That doesn't mean I wouldn't use floating point anywhere else. In aerospace in particular, I've used floating-point without issue, so I don't think you're point about currencies has any relevancy to the GP's comment regarding fuel estimation.