In 2000 403 trillion tonne-kilometres of freight were flown around the world. A tonne-kilometre is when one tonne (1000 kilograms) travels one kilometre. Together North American and Western European registered aircraft carry over half of the world total. Central Africa-registered aircraft carry 0.1% of all air freight in the world.
High counts of tonne-kilometres could be due to many heavy loads being transported short distances, lighter freight being moved a long distance, a combination of both, and/or many average weight loads being transported average distances.