TerraPass a company that allows the public to buy carbon offsets in the cap-and-trade system (you buy carbon polution that companies are selling basically) to offset CO2 polution from driving has introduced a flight calculator.
Visit the Flight Tracker to calculate the CO2 pollution from specific flight routes.
You can then buy a Terra Pass to offset the impact of your flight. Or you can buy Trees For the Future and help repair ecological damage in developing nations at the same time as you remove CO2 from the atmosphere.
I’ve purchased 1000 trees so far (cost $100) which will remove 25 tons of C)2 from the atmosphere every year for 40 years! I plan to buy another 1000 trees every year for the next 5 years so as to completely nutralize my carbon footprint.