E-piphany

I noticed something recently about the many, many airline loyalty miles that my family has accumulated over the years.

Loyalty miles began as a way for airlines to induce brand loyalty in a market that was very fractured post-deregulation (the U.S. airline industry was deregulated in 1978; the American Airlines and United Airlines loyalty programs were created in 1981…although Texas International Airlines is credited with creating the first loyalty program in 1979). In the Old Days, miles worked something like the punch card at the ice cream store, but instead of getting a free scoop of ice cream after ten purchases, it was a free trip after so many segments flown. Because airlines get compensated basically by the number of passenger-miles they create, the loyalty programs were tied to how many miles you flew. Fly more miles, get more miles. But the redemption was fixed: originally, 20,000 miles got you one round-trip domestic coach ticket anywhere the airline flew.

When you get your free scoop of ice cream, it isn’t the scooper’s decision what flavor you get. It’s yours. With ice cream, that’s no big deal; one flavor costs the ice cream parlor about the same amount to deliver to you as another. But with airlines, the problem is somewhat bigger.

Quantitative aside: experienced rates traders may see an echo of the bond-contract structure where it is the seller of the contract who gets to decide which bond to deliver. This optionality is worth something to the seller, and costs something to the buyer, so the bond contract trades at a lower price than it would if there were no delivery options. In this case, it is the buyer who gets to choose what product the seller must deliver (with limitations, of course). So it is very clear that loyalty programs, at least in the traditional structure where the price of the benefit was fixed at 20k or 25k miles, were very valuable to the customer. So did the customer pay more for a fare than he/she otherwise would, to get miles? We may never know.

When the award was “any flight [other than some blackout dates]” and the cost was “20,000 miles”, the strategy was fairly clear. You wanted to wait until you had to buy a high-priced ticket, and buy that ticket with miles instead. In fact, spending the miles on a $400 ticket had a potential opportunity cost because then you wouldn’t be able to spend them on a subsequent ticket that cost $500. So the strategy was to wait, because the option had value. Moreover, inflation worked in your favor as tickets over time rose. There was no realize cost of carry to penalize not spending the miles…so the strategy was to wait. Your loyalty miles were an inflation-linked bond, whose value was linked to airline fares. Actually, an option on an inflation-linked bond…but I digress.

This has changed.

A few years ago, airlines started varying the amount of miles needed to book certain tickets. Tickets on high-load-factor flights started to cost more. In a way, this was not terrible because it meant that some tickets were available at a higher cost, that previously would have been blacked out. So your 25,000-mile award wouldn’t buy the ticket, but you could get it for 50,000. This was successful, and over time what happened is that ever-finer gradations of mile-award-amounts-needed began to show up.

I took an hour this morning and went on United’s website. I priced economy, non-stop, round-trip tickets for EWR-LAX, EWR-ORD, EWR-DFW, EWR-IAD, EWR-BOS, and MIA-SEA(one stop as there were no directs), for March 24-March 26. I collected the price for each departure time. Then I collected the mileage required to buy the ticket in lieu of cash. The chart of this little experiment is below. The x-axis is the miles needed; the y-axis is the dollar cost, and each dot represents one fare pair.

You may notice that the blue dots are arranged in a surprisingly linear way, at least until 32,500 where it seems there is a cap of sorts. In fact, a linear regression line run through the points produces an r-squared of 0.88, and you can get it to 0.95 or so if you use an exponential curve. But the linear line is instructive because the slope of the line indicates that one airline mile on United is worth almost exactly 2.5 cents. As an aside, I didn’t check other loyalty programs but I would be surprised if the slope of American’s line or Delta’s line was meaningfully different.

The red line is where the old 25,000 award would be. If that was still the cost of a ticket, a buyer would not waste it on the tickets to the left of the line and would only use it on those to the right of the line.[1]

So, let’s call a spade a spade: one airline mile on United is 2.5 cents. When airfares go up, your pile of miles becomes less valuable in real terms. Loyalty miles are now indistinguishable from money, in the air travel marketplace.

Here’s the interesting part. Because loyalty miles are now money, the strategy that you the customer should take completely changes. Before, your best strategy was to wait, allow miles to accumulate, and only use them when prices spiked. Now, because miles are money, your best strategy is to spend them as quickly as you can. They don’t earn interest, so they are a wasting asset in real space. It doesn’t matter if you buy one $800 ticket for 32,000 miles, or two $400 tickets for 16,000 miles each. The value is exactly the same.[2] Ergo, they’re money. Not only that, they’re money that can only be spent on airline tickets, and they have a credit component because if the company goes out of business *poof* there go your miles.

Actually, they can be spent on other things, but the optimal way to spend them is probably on airline tickets. I looked at how many miles I would have to exchange to rent various car sizes from Avis in Newark, for two days starting March 24. I added these dots to the chart below.

So the final moral to this story is: don’t rent cars with airline miles!

[1] Class exam question: draw the consumer surplus that the airline reclaimed by changing the pricing structure.

[2] A small caveat to this would be if the current apparent cap at 32,500 for a coach economy class ticket is fixed, because over time more and more tickets would be pricey enough to be capped. However, I think it is unlikely airlines will hold a cap in that way.