>>whatev+QK2
Modern jetliners get a higher miles per gallon per seat than most US (ICE) cars. They easily beat any ICE car with a single occupant in miles per gallon equivalent. If you want to minimise fuel usage and can't find someone to share with, it's better to fly! The issue is almost entirely the distance travelled.
>>riirif+D93
It varies so much depending on passenger occupancy rates. Planes tend to run near 100%, and cars (at least in the US, although I'm sure other countries aren't much better) at near 20%.
Assuming 1mpg for the entire train, it needs at least 100 passengers to compare to a fully-occupied passenger plane.