There's a whole mini-industry around carbon accounting but (A) it's very hard to estimate accurately, (B) it will be gamed like any other metric, and (C) energy is good. We should focus on making energy cleaner and cheaper so that people can use it without guilt.
"carbon offset" is big business in the aviation world although I feel it's just virtue signalling. If they were serious about aiming for "carbon neutral" the plane would never take off in the first place! I admit this is a very simplistic view and likely I just don't understand the bigger picture about economics of carbon offsetting.
Aviation is one of the easiest cases because the amount of fuel burned is tracked and ~100% of the carbon in the fuel becomes CO2. Since there's currently no good alternative to hydrocarbon fuel, it's also a good case for biofuel or carbon capture (not offsets which are mostly fake).