Free market 101: charge passengers based on weight?
If you deliberately chose to purchase a seat you know does not fit your needs, then attempt to steal space from the person next to you, then you are the bad guy. Not the airline. If you think you deserve to be gifted free additional space you did not pay for, then you are the bad guy.
He said he was he not spilling over into the next seat.
(If airlines want to embarrass people, they need to do it in a tactful way. Like before buying the ticket. For instance, if your waist is over--whatever 50 inches, you need to buy two, but not on the plane in front of everyone. Airline have to go back catering to their custmers. Taking a flight seems just awful these days.)
Likewise, luggage is weighed at the airport, rather than what someone claims the weight is.
Now, I don't know the whole story of how the communication with Smith went down, but I 100% agree with the policy: If you can't lower the arm rest, you need to buy another seat.
Also, your suggestion "Like before buying the ticket" doesn't make sense. How is the airline to know someone is large enough to buy require 2 seats before they board?
I remember when this story came out, and there was plenty of backlash against Smith for going on his tirade, and some of it from other overweight people basically along the lines of "I know I'm overweight, and I know I have to deal with it by buying a second seat".
So an extra 100 lbs on every passenger is a drop in the bucket!
https://courses.washington.edu/ie337/Boeing%20Tour%20Facts.p...
Edit: the plane holds 328-550 depending on seat configuration per the above link. I went with the upper end of that range per consideration of the “safety considerations” indicating it is the upper end of that range that is being reconsidered.
Is the average American 100 lbs heavier than the average person from the rest of the world? Probably nowhere near that.
The problem case for weight are the regional jets (E190 etc) and to a lesser degree the 737/A320 family. Those tend to be weight limited enough that you need to offload passengers or baggage if it's too warm outside.
Of course, fuel is no different than any other weight, so the same rule would apply to the revenue load (people, bags, freight)—for every three pounds it cost you one pound of fuel.
Incidentally, I've always felt ticketing should be pro-rata wrt weight. Well, where 'always' is defined as 'since I obtained my FAA dispatcher license.'
/Acey
Better question: what fraction of airline's margins could one explain with the variation of passengers' weights? Airlines' pre-tax margins are low [1]. Almost any factor, meaningless or meaningful, will look tiny relative to revenues or costs.
[1] https://www.statista.com/statistics/225856/ebit-margin-of-co...
In terms of flight operating costs (FOC) per hour, about 16-36% according to the numbers for a 737-500 across for Continental/United/Southwest a few years ago.
It's very dependent on utilization. Fixed ownership (i.e. depreciation/leasing) costs start to dominate at low utilization rates.
Boeing 737‐500 FOC per block hour (~2017):
Crew Fuel Maint. Ownership Hrs/day
Continental $510 $430(19%) $ 651 $698 3.9
United $927 $487(16%) $1048 $510 4.3
Southwest $388 $537(36%) $ 251 $350 8.2
The same for the 737MAX.
https://www.nhlbi.nih.gov/health/educational/lose_wt/BMI/bmi...
(1) Yes I know link between a 'normal' BMI and health is complicated.
The weighing could be done at the end of the flight.
It's possible some people will actually get healthier. However, it's also much easier to lose 10lbs from dehydration and pooping than from losing fat (from my experience).