I don't think this is true unless you have a ridiculously high electricity bill. When I checked, one intercontinental retour flight was roughly equivalent to my yearly electricity bill, in terms of CO2 emissions. I have to admit I'm not sure how to reconcile this with CO2 credit prices, but I'm quite sure it's not really possible to offset the CO2 emissions of a intercontinental flight with 20 euro, that would mean that a minor tax on flights would make them practically carbon neutral, this is definitely not the case.

I think you've got your numbers badly wrong.

Here in the UK, the average household used 4,648kWh of electricity in 2010. The industry average in 2008 was 527g CO2e/kWh, giving average emissions from electricity use of 2449kg per household. The above figures are falling rapidly due to efficiency and decarbonisation.

A round-trip from LHR to JFK produces about 1800kg CO2e.

Reducing my electricity consumption by 10% would just barely offset the carbon emissions of a short haul trip within Europe. A frequent air traveller could easily produce an extra 10 tonnes a year without really noticing.

No, my electricity produce 22 gCO2eq/kWh for the last 12 months, it wont do much.