The head of Samoa Air Chris Langton says the airline's new pay by weight scheme is not discriminatory, instead it benefits all passengers.
The airline started weighing its customers and charging per kilo in November on some sectors and after little adverse reaction, it decided to roll the policy out on all flights.
Critics have called the policy discriminatory and humiliating.
But Mr Langton says it will eventually lead to lower costs for all its customers because of improved efficiency and heavier customers will have a more comfortable flight.
"When we do get somebody who's pretty big we try our best to make sure that they have a good trip and that they can recognise they're not just paying for their weight but they're getting the benefit of the payment with a much more comfortable seat and consideration."
Mr Langton says other airlines, reluctant to bring in such a policy, are watching his move closely as they can see business opportunities ahead.