Just to keep things in perspective, a fully laden 747 on a 12 hour flight will probably produce about 350 tonnes of CO2. To achieve the same effect in my O-360 engined puddle-jumper, I would need to fly it for around 4200 hours. I just might achieve that much if I continue flying at my current rate until my 70th birthday, but I suspect I will fall short.
(Assumptions for the 747 figure - fuel is uniform C11H24, 12 hour flight, 9400kg / hour in the cruise and an extra 700kg burnt on the ground.)