Note on booking Delta flights with Alaska miles

One of the great things about Alaska Airlines' Mileage Plan program is the ability to both credit paid flights operated by American Airlines and Delta Airlines, and redeem Mileage Plan miles for flights on either carrier (when low-level space is available).

I wrote back in February about free award changes and redeposits being a great benefit of Alaska MVP Gold and MVP Gold 75K elite status, since it applies to award bookings on partner airlines as well. In March, when I went to use that benefit again, I encountered an unexpected snag, one it's vitally important to be aware of if you use Mileage Plan as your primary frequent flyer program, as I do.

Delta enforces stricter fare construction rules on Alaska awards than on their own members

In the pre-2015 days of award charts and the deeply broken Delta booking engine, to piece together an international award trip you had one option: search leg-by-leg for low-level award space, then plug each leg into Delta's multi-city search tool.

With the improvements to the SkyMiles booking engine, and loss of stopovers, that's not only unnecessary, it's counterproductive. While before you could book low-level awards by stringing together low-level segments, now Delta will sometimes show different award availability for non-stop flights than for connecting itineraries. Here's an example of a flight from Boston to Detroit with availability only at the 20,000 SkyMile level:

And here's a connecting itinerary with the same 10:30 am flight — but now it's available at the low level:

If you want to fly to Detroit, and aren't checking a bag, you could of course book the connecting flight and get off in Detroit, although there are some risks to hidden-city ticketing. If you don't actually want to fly to Detroit, then if you're booking with Delta SkyMiles this doesn't affect you; just search for and book the connecting flight.

Here's the problem: when I attempted to book the same itinerary using Alaska Airlines Mileage Plan miles, the Alaska website returned the following error:

When I spoke to an Alaska representative about the issue, she looked into it and explained that Alaska could only book Delta flights when there was low-level availability on each component flight of an itinerary — even if Alaska's website shows space on the composed itinerary, and even if Delta is willing to book the complete itinerary for their own members.


It's hard to say in the abstract how big a problem this is or will become. For now, on most flights, most of the time, Delta award space on each leg of an itinerary roughly corresponds to the award space for the entire itinerary, and this problem doesn't arise.

On some itineraries, some of the time, especially when connecting through one or more Delta hub, this will be a huge problem since it will completely prevent an award from being booked with Mileage Plan miles at any price.

In any case, it's an issue anyone using Alaska Airlines' Mileage Plan as their primary frequent flyer program should be aware of.