Thanks, I stand corrected, however it does not apply for short haul flights (154g)

If travelling domestically, driving – even if it’s alone – is usually better than flying;

However on the other hand, most popular European airline boasts much lower numbers. I wonder how they achieved this figure.

Ryanair already has the lowest CO2 emissions per passenger/km of any major airline in Europe (66g) and by switching to Ryanair, passengers can now further reduce their CO2 emissions.