Jackonicko:
The graph below is from the
ATR website - it partially answers your question. (Note that the "train" figure includes the worst-case type of electricity generation from the emissions point of view.) Unfortunately the assumptions are not spelt out on the website, but based on
this document elsewhere on the ATR site , the aircraft seems to be assumed to be 100% full and the car to have two passengers.
Cheers
C.
