The heavier a plane is, the more av-gas is needed to fuel it.
The more av-gas is used to power a plane, the more expensive it is to run.
Therefore it makes sense for Samoa Air to charge passengers by weight rather than by seat.
The airline's decision to charge passengers according to their weight has prompted a mixed reaction, but a pay-as-you-weigh system seems perfectly fair to me.
I'm not coming at this from a position of righteousness, either. I'm at my all-time heaviest weight and the husband is a 1.95m slab of man, so it would cost us a fortune to travel if pay-as-you-weigh was adopted across all airlines.
However, even though it would cost us, I do think people and their luggage should be weighed together and the price calculated on the combined weight.
And it's probably an impossible dream but I would love to see two rows reserved at the rear of every aircraft that had extra-wide seats and extra leg room for the tall and the well built among us.
I'm so short I even have leg room on Cessnas, but travelling is misery for anyone bigger or taller than the average.
I'm sure some people support the higher charge for heavier passengers because it's a form of payback. Many people who have travelled, especially in the US, will know the misery of being crushed by a hugely overweight person who has spilled over into your seat.
If pay-as-you-weigh means these seathogs at least get hit in the pocket for the discomfort they inflict on innocent passengers, then that will be some small comfort as you hunt for your remote in the folds of the flesh of the person next to you.