[Retric]

First that’s excluding more efficient long haul flights. If you want a system wide view then you also need to include the costs associated with building and maintaining rail/road networks etc.

Also just like road, rail, and boats aircraft don’t get to fly hypothetically ideal paths from origin to destination. Actual MPG is distance traveled / fuel used not distance from the origin to destination / fuel used.

Not to mention most commercial flights are also moving freight on those same aircraft but that’s secondary.