Like anyone who does a fair amount of paid and award travel on Delta, I've been annoyed by their "flexible" award prices, which are generally calibrated to ensure you don't get too much value from your SkyMiles. On the other hand, if you keep a variety of points currencies around you always have the option of redeeming the one best suited for the flights you have in mind.
The real trouble comes about when trying to get value from one of Delta's partner award programs, like AeroMexico, Korean Air SKYPASS, or Air France/KLM Flying Blue. We used to say that airlines typically make "low-level" award space available to their partners. But with Delta's "what you see is what you get" pricing, that terminology doesn't make much sense. In fact, Delta awards at a variety of price points show in award searches as what used to be low-level "N" award seats.
What we'd really like to know is what kind of partner award space Delta makes available to their SkyTeam partners. Fortunately, Korean Air SKYPASS now shows Delta award availability online. I've been fiddling around with a variety of search terms and have a few preliminary observations.
Partner award space generally corresponds to "low-level" space
Drew at Travel is Free put together a sort of brute force Delta award chart based on an algorithm running award searches. If you can find flights at those prices then they'll typically be bookable as partner awards.
If you're using Korean Air SKYPASS you can only book roundtrip awards (although open jaws and stopovers are allowed), and I believe you can only search single-cabin awards online, but if you can find roundtrip award availability in the same cabin, there are good values on Delta. For example, a roundtrip on one of Delta's transcontinental Delta One flights costs 80,000 SkyMiles, but just 45,000 SKYPASS miles. Likewise roundtrip flights from the continental United States to Alaska and Hawaii cost just 25,000 SKYPASS miles in economy and 45,000 miles in first class.
I stumbled over a few tricks to keep in mind when booking Delta flights with SKYPASS miles. When searching for SkyTeam awards on the Korean Air website, you have to select "Economy Class," "Prestige Class," or "First Class." For flights in Delta's domestic first class cabins, you select "First Class," but flights in Delta One are coded as business class partner awards, which corresponds to "Prestige Class." There's no difference in cost for flights within North America including Hawaii and Alaska.
Sample booking: JFK-LAX, 6/1 - 7/17, Delta One: 80,000 SkyMiles, 65,000 Alaska Mileage Plan miles, 45,000 SKYPASS miles.
Partners generally have access to sub-low-level space
While Delta's flexible redemption rates generally punish SkyMiles members by charging them more for more expensive flights, they also sometimes show flights that are cheaper than the "low" award rate. In those instances I was able to find the same flights with Korean Air SKYPASS, although Korean Air naturally charged the higher, standard rate.
Sample booking: JFK-PDX, 6/2 - 6/8, Main Cabin: 24,000 SkyMiles, 25,000 Mileage Plan miles, 25,000 SKYPASS miles.
Partners have more creative routing rules
One big problem with "what you see is what you get" pricing is that even though you may have found Delta partner award space on an itinerary, Delta might not price it out at the low level through their multi-city pricing tool due to their own award routing rules. For example, this is a perfectly legal SKYPASS redemption for 25,000 miles: