They should charge by weight, would be much fairer on people who keep fit.
Pay less to heavier cabin crew members
However, I had a rather unpleasant flight once squashed between two undisputed overweight fat bastards. Not only did I have no arm rest, I had no shoulder space too. Oh, it was also a long haul.
Overweight may be a "safety" issue, but more so it impacts other passengers. Hardly seems fair when a passenger takes up other passengers space.
But I agree that weight and size (of passenger and luggage) should be used to decide price especially when it has a direct effect on the cost of the flight.
Not always true since muscle weighs more than fat. But generally if should be fair that those who are seriously oversized (whether with fat or muscle) have to pay more.They should charge by weight, would be much fairer on people who keep fit.
Andre the Giant did the right thing and booked two seats.