# Welcome to Qantas – could you please step on the scale?

Today, an anonymous guest post (from someone with an ANU connection) ponders airline pricing.

A recent article in the SMH reports that from February 1, Air France and KLM will begin charging obese passengers 75% of the cost of a second seat if they cannot fit into one seat. This story re-ignited an interesting question I’ve had regarding airline tickets. I have always been perplexed by the issue of pricing after a trip to the Middle East.

After spending far too much money on carpets in the souks, I arrived at the check-in counter at the airport to be told that my ticket only allowed 25kg of baggage and that my recent acquisitions had sent me 5kg over. If I wanted to take them with me, I had to pay the surcharge. The exact amount escapes me, but I was told it was to cover the cost of transporting the extra weight.

What puzzled me about the explanation was that standing at the next check-in counter was a sizable chap (possibly around 110kg) with 25kg of luggage. He wasn’t charged excess since his luggage was on the allowable limit, but if the price of a ticket represents the cost of transporting weight; your weight, surely his net impact on the overall weight of the plane is far greater? (I’m an average male, 175cm tall and weighing around 78kg). With my luggage, my total weight on the plane was 108kg, much less than the 145kg of my fellow passenger.

Simple flight dynamics says that the heavier the plane, the more fuel it will use to fly. Presumably, most other costs of operating an aircraft are fixed (salaries for crew, catering, landing and docking levies, lease payments on the aircraft), which leaves fuel. If the largest variable cost of running a plane is determined by the fuel used to transport the overall weight (plane, passengers and luggage) of the aircraft at takeoff, surely the current pricing mechanism for airline tickets is economically inefficient?

Wouldn’t it be far more efficient to charge people based on their total weight impact on the plane (i.e. body weight plus baggage)? That way, slim travellers with little luggage do not subsidise heavier people with large amount of baggage.

Any theories as to whether the suggestion of our anonymous poster could – well – fly?

## 22 thoughts on “Welcome to Qantas – could you please step on the scale?”

1. Jeremy says:

Legal problems (amongst others), i.e. impairment discrimination, and perhaps gender and age discrimination.  That’s the difference between people and baggage: both cost fuel, but the latter is more of a choice than the former.

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2. I think the incentive for people to lose weight quickly in order to qualify for a cheap ticket (would you have a weigh-in like at the boxing?) opens up a number of issues that no airline would want to deal with.

Maybe a toal weight ticker would suffice – maybe 125kg for person and luggage.  Then a seperate fee per kilo between 125 and 150, then an even greater fee per kilo from there.

Still, I think people on the whole are happy that we are all different but want to be treated equally, especially for factors (mostly) beyond our control.

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3. D. W. Griffiths says:

The economic formulation of Jeremy’s reply is that the price elasticity of luggage supply is larger than the price elasticity of your supply of body fat. Put another way, it’s easier to lighten your suitcase than to lighten your bathroom scales.

As a weight-loss incentive, a cheaper ticket just won’t cut it. One of the most intractable problems of “preventative health” seems to be that body weight is largely unresponsive to incentives. We thus have almost no useful techniques for getting obese people to lose weight. (Lap-band surgery works a bit.

Shrewd observers will notice that this doesn’t fully answer Andrew’s question. If the incentives won’t work, why don’t airlines just pocket the extra revenues? The deeper answer is that the heavy customers are less profitable but still profitable, and that social norms would ensure that the first airline to install scales would lose all their heavier customers.

Does someone have the metric on the fuel cost of flying one kilo of whatever from Sydney to Brisbane in a modern jet?

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4. Veltyen says:

Quick back of envelope calculations.
A 747-400 can travel 13,000 km on a full tank, carrying 525 passengers with 216,000 litres of fuel.
Or in other words, on the longest trips each passenger would use 400 litres.
Cargo weight is 220,000 kg, or 420 kg per passenger but remember, this also includes crew and expendables, and has the plane at the absolute tolerances of its frame.
Additionally this also includes their fuel. 400l of fuel would weigh about 320kg (density is about 0.8) meaning that for each passenger there is only about 100 kg.
This would mean that at most, on a full plane, you would need to fork out for 400 litres of fuel, or about 4 litres per kilo. At current prices that is about \$5.

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5. HeathG says:

@DW. You mention
<i>One of the most intractable problems of “preventative health” seems to be that body weight is largely unresponsive to incentives. We thus have almost no useful techniques for getting obese people to lose weight.</i>
Do you have some papers to back up your claim because I’d love to cite them next time someone suggests we need a “fat tax” on certain foods.  I might eat a large amount of chocolate and other “fat tax” targeted food, but I also play sport, run three times a week and walk about a kilometre (each way) to the train station each day.
If you want a real “fat tax”,  tax people who are actually fat.. i.e. tax those over their ideal weight by more than a certain %  and who don’t have a valid disability/medical condition excusing them. it might not be any more effective in changing peoples weight, but at least those who are within their healthy weight range aren’t punished for their occasional (or not so occasional) indulgence.

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6. HS says:

I think we may be mischaracterising the purpose of the weight excess fees. I don’t believe that the cost of the extra weight is solely intended to represent the added cost of carrying more weight. The truth is that the space and weight capacity for luggage on an aircraft is a scarce resource. Therefore a limit must be put to each passenger’s luggage. The airline arbitrarily provides an amount of that resource that each passenger has by right of the ticket (say, 25kg) and then opens the rest of the resource up to the market for excess luggage.

I don’t know anything about airlines but I wonder if they have a secondary market for any unsold weight/space, such as post.

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7. Ideally they would be measuring and charging on excess fat mass or excess body fat percentage rather than weight, since that is the bodily variable under travellers’ control (granted it is relatively inelastic). Why penalize people for genetic variation? Full immersion weighing at the airport, I don’t see it happening.

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8. D. W. Griffiths says:

H.S. – I agree with your point about the importance of space. Of course, the airlines also test your luggage separately for this.

If the weight (and space) can be sold in a secondary market does Andrew’s question – could you charge people based on body weight – become even more relevant?

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9. Pserp says:

No seriously this is just selfish thinking!
Of course, those who are lighter would argue in their own self interest that it should be done on body weight!
Airlines work on average passenger weights (which seem to be going up globally as we get fatter and fatter on calorie laden junk foods).  I would suppose that this is also probably as much to do with the logistics as it is for possible illegal discrimination of people based on their weight.
Hypothetically what if you bought your airline ticket 6 months ago based on 65kgs and over the xmas break you put on 5 kgs of weight?  are you prepared to pay more at check in?!  What if you put on 5kgs while on holiday? pay more to go home like the guy who bought too many carpets???
So by using an average weight it means that the airlines actually rely on underweight people to counter the overweight people.. if over the course of a financial year they find they are flying more weight than expected then perhaps they should change that average weight and reflect it in their cost base.  If the marketplace permits maybe the cost of airfares may increase to reflect that increase in cost base.
So under the current scheme just because you are lighter doesn’t mean you should be entitled to carry more luggage than a heavier person.

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10. Pserp says:

Yes the planes are both weight and space limited…

Yes there definitely is a secondary market.. its called freight which has typically been quite profitable (especially if you’re part of a cartel! tsk tsk for those naughty airlines for getting caught!).

They sell space in the hold which obviously has an overall space limitation shared with people’s luggage and overall weight limitation based on maximum takeoff weight of the whole plane less the fuel, passengers, luggage etc

As to the article on KLM charging obese passengers a surcharge for a second seat… yes seats are also a  limited commodity so on a full flight its not unreasonable to charge for that seat based on the fact they could have sold it to someone else and that the amenity of other passengers is significantly affected if they let a large passenger eat into other people’s personal space.  But quite rightly the fee will be refunded if the plane is not full as they cannot claim any opportunity cost on that seat anymore.

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11. Tim says:

I think you’ve all got it wrong.
The people who are already being discriminated against are the large/tall ones. I’m 6′ 3″, 90kgs, and I pay \$100 for my flight to Sydney and have to suffer the (relative) indignity of cramping myself into a tiny seat with no legroom. This is largely due to my genetic makeup. A 5’4″, 55kgs petite lady pays the same \$100 fee and gets to luxuriate in the same seat space, gleefully swinging her legs, clearly claiming more space than her genetically inherited frame should give her the right to.
Why am I not purchasing the same (relative) good for the same money?
The only just thing to do is to have different seat sizes that are matched to people’s heights and girths.
Oh, and I’m just starting. This size-based discrimination doesn’t stop there. I require more calories to survive than a smaller person, yet all food purchasing is volume-based.

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12. My brother is in the oil industry in Scotland. To get on the helicopter you weigh in with your luggage on the scale all in. If you + baggage is over  the limit for the trip – some one or something stays behind.

If you are too wide to fit thru the escape window/hatch you don’t get on – no apologies, no tears, no excuses.
The  ‘copter leaves on time.

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13. “Oh, and I’m just starting. This size-based discrimination doesn’t stop there. I require more calories to survive than a smaller person, yet all food purchasing is volume-based”
But you don’t have to ask someone to get stuff off the top shelf and you save on shoe leather because you take less steps due to longer stride. You dont have to be content with low hanging fruit. You can walk over puddles instead of through them.

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14. Tristan says:

HS is right.
The luggage compartment and passenger compartment are different.  They are not resources that can be traded.
Just get  jacket with big pockets and shove all your most dense things in that – many a time has this helped me get by the carryon luggage limit.

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15. prgpca says:

Veltyen
You say “This would mean that at most, on a full plane, you would need to fork out for 400 litres of fuel, or about 4 litres per kilo. At current prices that is about \$5.”   Don’t know where you have been for the past 10 years, but \$5 would get you about 5 litres of fuel, not 400.

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16. David M says:

prgpca,
I think you will find that Veltyen means “about 4 litres per kilo. At current prices that is about \$5” [per kilo].
Of course, this assumes that Jet Fuel is the equivalent price of unleaded petrol at the bowser, which it isn’t. The global average price for jet fuel at the refinery in the week of 15 Jan 2010 is US\$2.07/gallon (Source: IATA).
This would mean your 4 litres of fuel would cost you around AU\$2.

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17. prgpca says:

Thanks David M, that makes much more sense.

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18. Veltyen says:

As a followup, I did actually check the price/barrel of jetfuel in singapore for that fuel cost.
\$170 US per 160 litre barrel as of the start of this year. There were a couple of newspaper articles about it at the time.
To echo Tim’s point this is academic in my case anyway. As someone who is relatively tall (195cm) an economy flight a couple of years ago damaged my knee to the point of never willingly flying again.

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19. Dave says:

Discrimination is in the eye of the beholder.  The point of the post, surely, is that the writer feels discriminated against by being charged a higher price per kilo than the heavier customer.

Would it be discriminatory if a baker provided larger loaves (for the same price) to its larger customers?  Would it be discriminatory if a service station filled up your fuel tank – irrespective of capacity – for a fixed price?  Would it be discriminatory if a health insurer asked you your weight (I suspect they already do.) ?

As for tall flyers, the problem here surely is lack of choice, not discrimination.  Why don’t airlines have seats with varying legroom and charge accordingly (some do already for “exit seats”)?  I expect this will become common as internet booking allows seat selection at the time of ticket purchase.

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