I took your original point "caring about improving the world for others" to mean "you should make decent efforts/sacrifices to help others if you have the capacity".
That is, you should not go on this flight, because the CO2 released will make the world a worse place.
But if you have this moral obligation to help others, it seems like the much greater mistake here is to spend $1200/person on the flight. $1200 is enough to save ~240 children's lives for a year if donated to an effective charity (Helen Keller Foundation). Compared to that good, the moral harm of the CO2 released is a rounding error (someone mentioned a bit over 1 ton/person).
I've never understood the moral axiom that says "you need to make sacrifices for others, but only if those sacrifices are for carbon dioxide release. You don't have to make much smaller sacrifices which do vastly more good". That to me seems clearly absurd - can you help me understand what mistake I'm making?
To be clear, I'm not saying it's wrong to cut your carbon footprint - I'm saying that if there's a moral compulsion to do that, it seems like there's a stronger moral compulsion to donate a high % of your worth to effective charities. But nobody every seems to think that is the case!