Which is to say, the world-wide policy priorities need to be on transportation (other than flying), electricity production and industrial emissions [0]. Giving up coal and petrol cars has potentially much greater impact than giving up flying.
That said, when you consider the CO2 emissions that you cause yourself directly, a good rule of thumb is that as soon as you fly at all, CO2 from flying dwarfs all your other CO2 emissions. On the individual level, not flying, flying less, or offsetting carbon emissions from flying has the biggest impact.
[0] https://www.epa.gov/ghgemissions/sources-greenhouse-gas-emis...