It is possible to earn miles for 2 seats on the same flight. Customers of size that have to purchase a second seat can earn frequent flyer miles for it.

Each airline has specific policies for ‘Customer of size’ and expects them to buy an additional seat if they do not fit comfortably with the armrests in down position. The price of the second seat is the same as the original and passengers can either purchase the additional seat in advance or at the gate. In fact, Alaska Airlines allows passengers to use Companion Fare discount codes or miles towards booking the second seat. If the flight is not full and adjacent seats are available, the second seat fare is refunded. Whereas, if the flight is full and the second seat fare cannot be refunded, passengers can earn frequent flyer miles for the 2 seats.

While every airline handles this slightly differently, Alaska Airlines does a good job in outlining the policies;

If you are not eligible for a refund of the second seat because your flights departed full, and you are an Alaska Airlines Mileage Plan™ member, you can receive Mileage Plan™ Bonus Miles for the second seat only on flights operated by Alaska Airlines, Horizon Air, PenAir between Anchorage and Dutch Harbor, and SkyWest flight series 3300-3499. The Bonus Miles are equivalent to the mileage you received for each eligible flown segment. You may contact Customer Care at 1-800-654-5669 to request miles once you have completed travel. Please note, these Bonus Miles for the second seat do not count towards Elite Status qualification.

Can anyone purchase two seats and earn miles?

Unfortunately, not quite. Here is the text from Alaska Airlines (emphasis my own);

The option to purchase an extra seat is available only to those individuals who require this service based on our seat dimensions. The purchase of an additional seat is required for anyone who cannot comfortably travel with the armrests in the down position. Any customer who purchases a second seat, and who does not meet the criteria described in our second seat policy, will be ineligible for a refund of the second seat.

Notice that it does not mention anything about earning of miles. You could argue that anyone should be able to book 2 seats and earn miles for the second seat – clutching on straws here.

Before you run to try this, consider comparing fare for 2 seats with one First class ticket. It maybe cheaper to travel upfront and earn 200% miles.

Alaska Airlines Customer of Size Seating guidelines.

Take Away

Airline policies on ‘Customer of size’ have evolved significantly and the ability to earn miles on the additional seat is a good perk. Airlines have complete discretion in determining passengers that meet the guidelines for purchasing a second (or third) seat.

Have you had to purchase an additional seat? Share your experience with a comment below.