[aeroman]

Another way to think about it is in terms of average person years

  American: ~15 tonnes CO2 per year - 126 years
  European: ~10 tonnes CO2 per year - 190 years
  World average: ~5 tonnes CO2 per year - 379 years

This one plane emits many lifetimes of CO2 per year.

I don't think this accounts for non-CO2 impacts either (e.g. contrails). Multiply the years by about 2 as an estimate of that.