There are a few other aspects to consider, like radiative forcing[1], which add a significant multiplier onto the basic CO2 released from burning the fuel. For one take on calculation of emissions, see how MyClimate (a carbon offsetting service) calculate total CO2 emissions[2].

[1] https://en.wikipedia.org/wiki/Environmental_impact_of_aviati... [2] https://www.myclimate.org/fileadmin/user_upload/myclimate_-_...