Airlines should charge obese passengers more, a Norwegian economist has suggested, arguing that “pay as you weigh” pricing would bring health, financial and environmental dividends.

Bharat Bhatta, an associate professor at Sogn og Fjordane University College, said that airlines should follow other transport sectors and charge by space and weight.

“To the degree that passengers lose weight and therefore reduce fares, the savings that result are net benefits to the passengers,” Bhatta wrote this week in the Journal of Revenue and Pricing Management.

“As a plane of a given make and model can accommodate more lightweight passengers, it may also reward airlines” and reduce the use of environmentally costly fuel.

Bhatta put together three models for what he called “pay as you weigh airline pricing.”

The first would charge passengers according to how much they and their baggage weighed. It would set a rate for pounds (kg) per passenger so that someone weighing 130 pounds (59 kg) would pay half the fare of 260-pound (118-kg) person.

A second model would use a fixed base rate, with an extra charge for heavier passengers to cover the extra costs. Under this option, every passenger would have a different fare.

Bhatta’s preferred option was the third, where the same fare would be charged if a passenger was of average weight. A discount or extra charge would be used if the passenger was above or below a certain limit.

That would lead to three kinds of fares – high, average and low, Bhatta said.

Airlines have grappled for years with how to deal with larger passengers as waistlines have steadily expanded. Such carriers as Air France and Southwest Airlines allow overweight passengers to buy extra seats and get a refund on them.

Asked about charging heavier passengers extra, Southwest spokesman Chris Mainz said: “We have our own policies in place and don’t anticipate changing those.”

United Air Lines Inc requires passengers who cannot fit comfortably into a single seat to buy another one. A spokeswoman said the carrier would not discuss “future pricing.”

About two-thirds of U.S. adults are obese or overweight.

In a 2010 online survey for the travel website Skyscanner (www.skyscanner.net), 76 percent of travelers said airlines should charge overweight passengers more if they needed an extra seat.