It may not scale, but it's not greenwashing - for it to be green washing, you'd need either claims of lower co2 to be false, or pretend that this solves the issue completely.
Lufthansa, at least - when I checked - made no such claim. I reviewed their compensaid site thoroughly (afraid it's just greenwashing), and their communication seems very honest.
My dictionary defines greenwashing as "misleading or deceptive publicity disseminated by an organization so as to present an environmentally responsible public image".
Here in the US, we have a corn-farming industry that has captured the Agriculture department and can block passage of essential legislation. To be expected: legislation proposed in Congress that all US jet fuel henceforth contain X% bio-product.
Lufthansa, at least - when I checked - made no such claim. I reviewed their compensaid site thoroughly (afraid it's just greenwashing), and their communication seems very honest.