I was basically paraphrasing this:

https://www.nytimes.com/2013/01/27/sunday-review/the-biggest...

"For many people reading this, air travel is their most serious environmental sin. One round-trip flight from New York to Europe or to San Francisco creates a warming effect equivalent to 2 or 3 tons of carbon dioxide per person. The average American generates about 19 tons of carbon dioxide a year; the average European, 10."

Seems like there's some tricky math going on, notice: "equivalent" in the above quote:

http://www.carbonindependent.org/sources_aviation.html

This calculates 180 kg CO2/hour per passenger. So 8 hours or so between NYC and Paris? 1,440 kg. 1.6 tons. Not quite a few orders of magnitude.

Once through all the calculations, the above then states, "The CO2 emissions are therefore rounded up and the Carbon Independent calculator takes a values of 250 kg i.e. ¼ tonne CO2 equivalent per hour flying."

So that's more like 4 tons to Paris. (on Basis 1)