Given that we're looking at order-of-magnitude differences, that's "equivalently efficient".

The actual efficiencies depend tremendously on the range of the trip, the loading of the aircraft (or car), and base vehicle efficiency.

But ~30 - 40 passenger miles/gallon are possible in either.

For cargo, the (again, very rough) numbers are:

Ship: 514 ton * mile / gallon

Rail: 202 ton * mile / gallon

Truck: 59 ton * mile / gallon

Air: 13 ton * mile / gallon

Something I had cause to look up the other day as I was trying to figure out how to ship my M-1 Main Battle Tank.

https://plus.google.com/104092656004159577193/posts/MZ5Pi7AT...