[RedDevil]

It depends on the fuel load too.
My nephew is a pilot flying 747s for KLM. I thought he said it uses 8 kilos of fuel per kilometer, which would be around 2500 gallon per hour.
But that could be with the tanks near empty; if full the plane can be over 50% heavier.
I bet anything in the range from 70 to 100 mpgpp is about right.

Ships are terrible for mpgpp, especially the fast ones.
I once took a ferry from Lübeck, Germany to Helsinki, Finland. 1100 km in 23 hours at a speed of 56 km/hour. Enough to break the ice up to 200 meters away by the wake alone. The ferry doubles as an ice breaker.
(not that that was necessary in the record heat wave at the time)
It used 30 metric tonnes of diesel fuel per hour. 700,000 liters for the trip. Over 300 liters (80 gallons) per passenger. 9 mpgpp...

In the weekends it did not use its turbine jet engines but conventional piston engines, taking almost twice as long for the trip but using only 4 tonnes of diesel per hour.
Weekend trips are favorite with the Fins as they get 2 whole days on board to enjoy the view of the Baltic sea and the tax free liquor shop.