Air France has clarified their position on overweight passengers, making it clear that larger passengers will be asked to buy a second ticket for 75% of the full price. If the plane is found to have spare seats anyway, the price of the second ticket will be refunded.
If they don't reserve a second seat they may not be allowed to board if there is not an unoccupied adjoining seat, AP notes. An Air France spokesman called the policy "a question of security."
The problem of obese passengers has become a headache for airlines. Southwest Airlines led the way in asking overweight passengers to purchase another seat. The Independent writes:
Obese passengers comprise a growing problem for airlines on three counts. First, with average weight across the population rising, fuel consumption is increased. Next, with more overweight flyers, more passengers experience discomfort from sitting next to them. And with airlines collectively filling a higher proportion of seats, there is literally less room for manoeuvre on board for the cabin crew to shuffle passengers around.
CNN reports that a third of Americans are now classified as obese, yet the width of a coach airline seat has changed little in decades.
For a visual explanation of the problem, see the photo with this article.